Beetham W P
Med Clin North Am. 1979 Mar;63(2):433-9. doi: 10.1016/s0025-7125(16)31708-4.
Diffuse aching and stiffness may be caused by a fibrositis syndrome or by psychogenic rheumatism. If fibrositis is present, a careful search for underlying disease is made, and appropriate therapy started depending upon the results of all diagnostic studies.