What is pain? It might seem like an easy question. The answer, however, depends on who you ask.

Some say pain is a warning signal that something is damaged, but what about pain-free major trauma? Some say pain is the body’s way of telling you something is wrong, but what about phantom limb pain, where the painful body part is not even there?

Pain scientists are reasonably agreed that pain is an unpleasant feeling in our body that makes us want to stop and change our behaviour. We no longer think of pain as a measure of tissue damage – it doesn’t actually work that way even in highly controlled experiments. We now think of pain as a complex and highly sophisticated protective mechanism.

How does pain work?

Our body contains specialised nerves that detect potentially dangerous changes in temperature, chemical balance or pressure. These “danger detectors” (or “nociceptors”) send alerts to the brain, but they cannot send pain to the brain because all pain is made by the brain.