The rate of musculoskeletal pain in adolescent and adult populations is examined, with a focus on three commonly reported pain disorders: shoulder pain, low back pain and fibromyalgia/chronic widespread pain. There is a paucity of data on musculoskeletal pain in adolescent populations. Those studies available suggest that pain is common, although the actual rates are unclear. This is probably due to differences in study methodologies and populations. Pain is commonly reported among adult populations, with almost one fifth reporting widespread pain, one third shoulder pain, and up to one half reporting low back pain in a 1-month period. The prevalence of pain varies within specific population subgroups; group factors (including socioeconomic status, ethnicity and race) and individual factors (smoking, diet, and psychological status) are all associated with the reporting of musculoskeletal pain. However, the precise nature of these relationships, and particularly the mechanisms of association, are unclear and require further investigation.