About pain

Learn about pain, how it can be triggered and how you can better manage your pain.

Last updated: 28 Oct 2023 · 8 min read

Pain is defined by the International Association for the Study of Pain, as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage”. This is the revised IASP definition as of 2020.

Why do we experience Pain?

Pain is one of the body’s important alarm systems, designed to protect us and warn us that we are under threat. When a person experiences pain, one of the most natural responses is for that person to give attention to where the pain is coming from, or discover what is causing the pain or threat.

What is Acute Pain?

Acute pain (Pain that resolves with tissue healing, which most organisations define as pain lasting less than 3 (or 6) months) most commonly occurs when our physical-self has been hurt, or is in danger of being hurt. Acute pain usually occurs in response to hurt or illness (for example, an acute back ‘strain’, a sprained ankle, a strained muscle or other conditions like appendicitis). Acute pain initially protects us. The experience of acute pain is designed to help stop us from injuring ourselves in the same way again: we remember what happened and try and limit the risk of that happening again. Acute pain is designed to allow the body time to repair and recover.

For most people, acute pain is easily understood. Most of us have had many experiences of pain, from infancy (for example, starting with colic and the pain of teething), to early childhood (scratches, cuts, knocks, broken bones) and adolescence (period pain for young women). Usually, the body part which is affected, visibly heals and our pain reduces. Or, if pain is related to illness, the illness passes and the pain gets better or reduces. The memory of pain following injury or illness is an important part of our learning. If you put your hand on a hot plate, it burns, and so you learn to avoid putting your hand on a hot plate. It does not stop you from cooking each day! In acute pain, this memory and learning experience has an important protective function.

What is Chronic Pain?

In “Chronic” or “Persistent” pain, the physical hurt (such as low back pain) or illness (appendicitis) has often partially or fully resolved (healed), and yet pain persists1. In some cases, the pain might even be worse than it was originally. Chronic pain or persistent pain is defined as “pain that continues after an injury has healed or after an illness has passed“. In some cases, there is no clear initial injury or illness, for example Fibromyalgia. This does not mean the pain is not real!

When you experience acute pain, the problem usually relates to local tissue injury, infection or inflammation. However, with chronic pain, the problem is often less strongly related to local tissues and involves a broader (systemic) problem1. In acute pain most of the “receptors” (called nociceptors) tend to be mainly localised at the site of any infection, inflammation or injury – the body’s systems are designed to recognise the injury or damage and coordinate the mind and body to favour recovery.

In chronic pain, things change: there is growing involvement from other body systems (for example, the immune system, the sleep system, the hormonal system, the endocrine system). Changes occur in the way in which the nervous system interprets normal input or information: things that might cause pain normally, can cause much more pain and things that don’t normally hurt (e.g. normal daily movement or activities, gentle touch) can actually be painful. This is because the nervous system is not hard-wired but plastic, and the changes are due to the neuroplasticity of the nervous system1 and other systems, including the immune and endocrine systems2. These neuroplastic changes in the nervous system contribute to ongoing pain1.

While treatment and management of acute pain may be more focused on the immediate tissue injury or the illness initially, treatment and management for a person with a chronic pain problem must also address broader body-mind systems (for example, immune, nervous, hormonal, behavioural and emotional contributors to pain)1,3.

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Why is pain a problem?

Our nervous system is designed to learn. This ability reflects the dynamic and plastic nature of the nervous system. It is not hard-wired but capable of constant change: this capability is known as “neuroplasticity1. Sometimes these changes mean pain can persist, although the initial injury has healed. This is when pain becomes a problem, especially when pain starts to affect how we think, feel, act and interact with family, friends and others.

What can I do?

There is a lot you can do to help with pain, although there is no cure for pain. Pain when it persists is complex, and the different factors that can contribute to your pain will be different from those that affect others.

What is really important is to understand what your specific mix of factors are, and then with your health professional (team) to work together to plan a way through. It can be very challenging to find the right people and the right treatments. painHEALTH, provides you with current scientifically-based information and tools to help educate you and guide you about how you can co-manage your musculoskeletal pain. Using these pain management tools and guidance, along with support from your health professional (team), you can better manage your pain.

Approaching pain

Pain types


Using a pain team

Pain self-checks

Pain Australia - Fact sheets

  1. Siddall PJ. Neuroplasticity and pain: what does it all mean? The Medical journal of Australia 2013; 198(4): 177-8. [PubMed]
  2. Grace PM, Hutchinson MR, Maier SF, Watkins LR. Pathological pain and the neuroimmune interface. Nat Rev Immunol 2014; 14(4): 217-31. [PubMed]
  3. Moseley GL, Flor H. Targeting cortical representations in the treatment of chronic pain: a review. Neurorehabilitation and neural repair 2012; 26(6): 646-52. [PubMed]
  4. McCarberg B, Peppin J. Pain Pathways and Nervous System Plasticity: Learning and Memory in Pain, 2019 Dec 1;20(12):2421-2437 [PubMed]

This module has been developed by Associate Professor Helen Slater, PhD, FACP, School of Physiotherapy, Curtin University, Perth, Australia. The information in this module is based on current best evidence research and clinical practice.


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