There are four ways that pain can be activated:- Normal stress on abnormal tissue: Example: Walking (normal stress) with a degenerated knee (abnormal tissue).
- Abnormal stress on normal tissue: Example: Healthy person (normal tissue) who sits with a slouched posture (abnormal stress).
- Abnormal stress on abnormal tissue: Example: Sleeping on stomach (abnormal stress) with a pinched nerve in the neck (abnormal tissue).
- Chemical stress: Inflammation, infection or trauma.
