" Pain is a complex, unpleasant sensory and emotional experience, which many patients suffer in the course of their lives. Fortunately, most of these instances re-solve spontaneously and are due to acute problems. However, particularly with musculoskeletal pain, the potential for a long-term problem is present; appropriate pain management can be essential in helping the patient return to full functioning. In addition to the nociceptive stimulus, cultural influences, the patient's own expectation, emotional factors such as fear and anxiety, loss of control, depression, primary / secondary and tertiary gain, and predisposing psychological factors - all can influence the amount of pain the patient reports."
http://www.pelvicpain.org/newsletter/1998_july.html
[Hint: If you decide to print-out this article, this information begins on page 6.]