Pain lasting more than three months is called chronic pain. Because it can persist after tissue damage has healed, examining the original site alone does not explain it.

The central mechanism is sensitisation. As pain signals repeat, the nervous system becomes more responsive to them, and weaker stimuli than before begin to hurt.

Avoidance behaviour compounds this. Pain discourages movement, less movement reduces strength and range of motion, and the same action then hurts more. That is the structure of the cycle.

The recommended approach is not to eliminate pain but to restore the capacity to cope with it, with short bouts of regular movement, slow breathing and adequate sleep as basic elements.

In practice, frequency matters more than intensity. Rehabilitation practitioners generally hold that several short sessions reduce avoidance responses more effectively than one long daily effort.

Caution is warranted, though. Sudden pain, pain at night, and pain accompanied by weight loss or fever are signals to look for other causes and are not matters for self-management.

This paper recommends no particular treatment or product. What is summarised here is general health information; diagnosis and treatment belong to medical professionals.