The purpose of this study is to explore the perspectives of health professionals on chronic (non-malignant) musculoskeletal pain in adolescence and young adulthood. The prevalence of this pain symptom is rising for ten years, and most of the time the diagnosis is complex. Health professionals have to differentiate between the continuing activity of a somatic problem, some painful sequelae, a low threshold for the perception of pain, and psychological symptoms with somatic expression. Diagnosis in this case takes time, and is a matter of trained specialists. No protocol exists to assess the sub-clinical symptoms which will be used to help doing this complex task.