Chronic back pain is a very important and costly condition in advanced industrial societies which is the chief cause of limitation of physical function in younger people under 45. The definition of chronic is variable and can be taken to be a pain persisting beyond the expected healing time of the tissues which may have been damaged in the acute back pain event. This is often taken to be beyond twelve weeks as much of the soft tissue healing will have occurred at that point. Acute pain serves a biological purpose to warn us to stop doing the aggravating activity and to take care of the injured part, however chronic pain appears to have no …