It may seem obvious, but the main objective in patient evaluation is to make a diagnosis of the pain disease state as well as to identify the source of the pain. Determining the source of the pain can be extremely challenging because of the vast number of structures that can generate pain. Pain can arise from bones, joints, muscles, ligaments, nerve structures, and/or alterations in vascular supply. In addition, pain has numerous etiologies, ranging from structural malalignment to somatoform disorders. Pain also may arise from several different pain generators, and make the picture more complex and difficult to diagnose and treat.