Chronic widespread pain
Chronic widespread pain covers a variety of diagnoses, some specific (e.g., fibromyalgia) and some diffuse, that meet specific diagnostic criteria for the location of pain. Although the pain is real, the patient may have a low pain threshold and increased levels of psychological distress; the patient may meet the diagnostic criteria for major depressive disorder or other specific conditions. Preexisting emotional distress may make the patient more vulnerable, but there is also substantial evidence for generic predisposition as well; these should not be considered psychosomatic. 
Pain is considered widespread when all of the following are present: pain in the left and right sides of the body, pain above and below below the waist, and axial skeletal pain (cervical spine or anterior chest or thoracic spine or low back). In this definition, shoulder and buttock pain is considered as pain for each involved side. "Low back" pain is considered lower segment pain.
- K.L. Limer; B.I. Nicholl; W. Thomson; J. McBeth (2008), "Exploring the Genetic Susceptibility of Chronic Widespread Pain: The Tender Points in Genetic Association Studies", Rheumatology 47 (6): 572-577
- Wolfe F, Smythe HA, Yunus MB, Bennett RM, Bombardier C, Goldenberg DL, et al. (1990), "The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the multicenter criteria committee.", Arthritis Rheum 33: 160-172