Pain is defined as; “An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”1.

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What is Pain?

Pain – and especially chronic pain – is a conscious experience that’s influenced by your personal memories, emotions, thoughts, genes and health issues2.

  • Pain is a personal experience and your individual experience of pain will be affected by biological, mental and social factors to varying degrees.
  • Your experience of pain is more than just what your sensory nerves pick up.
  • Your concept of pain is something you learn and develop over the course of your life.
  • While pain usually serves to protect you from harm, it can negatively impact your life functionally, psychologically and socially1.

Pain can be categorised into acute and chronic pain3

Acute pain

Is caused by a specific disease or injury and serves a biological purpose4. It plays a protective role in the body, demanding immediate action and prompting you to reflexively withdraw from something too cold, hot or sharp that could cause your bodily harm5. Acute pain can be divided into:

Nociceptive pain

Which is triggered by an intense stimulus, such as touching a hot stove. It triggers an immediate action – you quickly remove your hand from the stove and, hopefully, avoid serious injury in the process5. It plays an important role – if you didn’t feel your hand burning, you would leave it on the stove and it could burn so badly that you could lose the ability to use it.

Inflammatory pain

Which creates heightened sensory awareness around an area of your body when you’ve been hurt5. If you’ve injured a joint, for example, moving the joint would suddenly feel painful because your body wants you to keep the injured joint still so it can heal5.

Chronic pain

Is defined lasting for longer than three months and is a complex sensory and emotional experience that differs from person to person6. It is a disease in its own right; not a symptom2. Unlike acute pain, it serves no useful biological purpose4. Some people are naturally susceptible to pain hypersensitivity and the conversion of acute pain into chronic pain5. Chronic pain can be divided into:

Neuropathic pain

Which happens as the result of damage to your nervous system5.

Dysfunctional pain

When you feel pain but there is no damage or inflammation. Examples include fibromyalgia, irritable bowel syndrome and tension type headaches5.

Know the Signs

General chronic pain

  • Lasts longer than three months2,6
  • Creates changes in the brain that are visible on a scan5,6
  • May be located in one specific area of the body or widespread6
  • Manifests in different ways at different times (e.g. Patient will suffer from inflammatory bowel disease and, as those symptoms recede, fibromyalgia symptoms become more prominent) 6
  • Fatigue6
  • Poor sleep6
  • Brain fog6
  • Anxiety and depression6

Neuropathic pain7

  • Excruciating pain when anything touches your skin
  • Sudden intense burning sensation for no reason
  • Sudden bursts of pins and needles
  • Crushing pain in your “phantom foot” after an amputation
  • Band of searing pain wrapping around your body after a spinal cord injury

Causes of Pain

Nociceptive acute pain

Is a protective mechanism that your body deploys when it senses that you’re at risk of physical damage as a result of disease or injury5. It is not a problem, except in specific cases, such as surgery, where it’s necessary to damage the tissue so the natural nociceptive response needs to be suppressed5.

Inflammatory acute pain

Is caused by the immune system being triggered into action in response to an injury or infection5.

Neuropathic chronic pain

Occurs as a result of damage to your nervous system – caused by mechanical trauma, metabolic diseases, neurotoxic chemicals, infection, or tumour invasion – which causes you to feel pain for no apparent reason or more severely than is appropriate. This is most commonly the result of a spinal cord injury, stroke or multiple sclerosis7.

Dysfunctional chronic pain

Is a malfunction of the nervous system and can be considered a disease in its own right. You feel pain when there is no evident harmful stimulus, no sign of inflammation and no damage to the nervous system7. This is seen in conditions such as fibromyalgia, irritable bowel syndrome (IBS) and interstitial cystitis (a type of chronic bladder pain). In these conditions, pain signals inside your central nervous system become spontaneously amplified and the processing of stimuli becomes altered7.

Get Diagnosed

You can help your healthcare provider by explaining6:

  • Where it hurts
  • How much it hurts
  • How unpleasant the experience is for you
  • How you understand the pain based on experience

Neuropathic pain

Is caused by damage to the nervous system or a disease that affects the nervous system6. Therefore, you would need to be diagnosed with a disease known to be associated with this type of pain (e.g. stroke or shingles) or go for tests that would allow your medical provider to see the nerve damage, such as a biopsy or a scan6.

Pain Pathway Explained12

How your body senses and processes acute pain:

  • Pain sensors in your skin called nociceptors pick up a stimulus that could cause harm – such as extreme heat or cold, pressure or a chemical stimulis.
  • The information is converted into an electrical signal that passes through your nervous system to your spinal cord.
  • From your spinal cord, the signal is transmitted to your brain.
  • When the signal reaches your brain, it gets processed and interpreted and you feel pain.
  • Your brain then sends a new message back down your spinal cord to the nerves that are in charge of action and you react to the pain – such as pulling your hand out of ice water.
  • Pain tolerance is your ability to ignore pain of a certain intensity and duration. The degree and length of pain that you are able to tolerate varies from person to person and is influenced by many factors – including personality, previous experience of pain, gender, and the circumstances under which you’re experiencing the pain.

Treating Pain

There are many types of medication available for treating pain, so it’s important to have a good understanding of your pain and its severity to ensure that you get the best option for your situation. Following these guidelines will help you manage your pain better8.

Usually for acute pain, your healthcare provider would start with strong medication and then decrease the dosage as you feel better, while with chronic pain, they would usually start with a mild dosage and increase it as necessary. It’s important to go for follow-up consultations in order to assess your medication and whether your dosage needs to be changed8.

Generally, it’s better to take oral medication and only administer a drip or suppository when necessary.

If your healthcare provider recommends a schedule of when to take your medication, be sure to stick to it rather than only taking medication when you feel you need it.

Painkillers should be matched to the intensity of your pain so it’s important to see your healthcare provider so you can get a proper assessment.

Treatment Options

Medical treatment options

How you treat pain can be viewed like a ladder, where different “rungs” represent severity of pain and corresponding treatment8.

  • Mild pain: Non-opioid painkillers such as non-steroidal anti-inflammatory drugs (NSAIDs) or paracetamol.
  • Moderate pain: Weak opioids (such as codeine or tramadol) with or without non-opioid painkillers.
  • Severe, persistent pain: Potent opioids (such as morphine) with or without non-opioid painkillers.

Any of these medications may be combined with other treatments called adjuvants or co-analgesics – these are medicines that aren’t usually prescribed for pain, but they can help to provide pain relief in the case of certain conditions. Examples include some antidepressants, anticonvulsants and topical corticosteroids8.

Non-medical treatment options

These may be recommended alongside medication in some cases8. Examples include:

  • Yoga
  • Acupuncture
  • Psychotherapy
  • Occupational therapy8

The transition from acute pain to chronic pain is believed to be a result of a fault in the brain’s ability to reorganise itself and create new neural connections after acute pain9.

This involves three processes: the intensity with which sensory nerves pick up pain, how reactive the central nervous system is to pain and how the brain processes pain signals9. By targeting these processes, it may be possible to prevent the development of chronic pain9.

There is also evidence that treating acute pain as soon as possible can help prevent chronic pain from developing10. In other cases, such as with chronic lower back pain, the focus should be on eliminating the cause – in other words, preventing re-injury10.

Faces Pain Scale11

This visual tool is a useful way to help young children describe the level of pain they’re feeling.

It’s based on the popular numerical scale where pain is rated from 0 (no pain) to 10 (extreme pain) but instead of numbers, children are shown pictures of facial expressions, ranging from relaxed to grimacing. Once the child understands that the relaxed faced indicates no pain and the grimace indicates severe pain, they simply need to point to a face on the continuum that corresponds with how they’re feeling.

Responsible Opioid Use

Opioids, such as codeine, tramadol and hydrocodone, are commonly prescribed for the treatment of pain, but the danger is that they are also highly addictive. Therefore, they should only be used when necessary and your healthcare provider may also switch between different opioids to give you maximum pain relief, while minimising side-effects8.


  1. Raja, S., et al. The revised International Association for the Study of Pain definition of pain: concepts, challenges, and compromises. PAIN. 161, 9. 1976-1982. (2020)
  2. Tracey, I. & Mantyh, P. The Cerebral Signature for Pain Perception and Its Modulation. Neuron. 55, 3. 377-391. (2007)
  3. Auvenshine, R. C. Acute vs. Chronic Pain. Tex. Dent. J. 117, 7. 14–20. (2000).
  4. Grichnik, K. P. & Ferrante, F. M. The Difference Between Acute and Chronic Pain. Mt. Sinai J. Med. 58,3. 217–220. (1991)
  5. Woolf, C. J. What is This Thing Called Pain? J. Clin. Investig. 120, 11. 3742–3744. (2010)
  6. Crofford, L. J. Chronic Pain: Where the Body Meets the Brain. Trans Am Clin Climatol Assoc. 126.167-83. (2015)
  7. Costigan, M., et al. Neuropathic Pain: A Maladaptive Response of the Nervous System to Damage. Annu Rev Neurosci. 32,1-32. (2009)
  8. Anekar, A. A. & Cascella, M. WHO Analgesic Ladder. In: StatPearls. Treasure Island (FL): StatPearls Publishing. (2021)
  9. McGreevy K., et al. Preventing Chronic Pain following Acute Pain: Risk Factors, Preventive Strategies, and their Efficacy. Eur. J. Pain. 5, 2. 365–372. (2011)
  10. Gewandter, J., et al. Research Design Considerations for Chronic Pain Prevention Clinical Trials: IMMPACT recommendations. PAIN Reports. 6, 1. e895. (2021)
  11. Hunter, M., et al. And Evaluation of the Faces Pain Scale with Young Children. J. Pain Symptom Manag. 20, 2. 122-129. (2000)
  12. Osterweiss, M., et al. The Anatomy and Physiology of Pain. In: Pain and Disability: Clinical, Behavioral, and Public Policy Perspectives. National Academies Press. (1987)

Learn more about other areas of pain.

Learn more about other areas of pain.