A MACHINIST WAS ASSISTING A WELDER INSTALL SPACER PIPES IN TUBES AND ALIGN FLANGES. AFTER SEVERAL HOURS THE MACHINIST'S LEFT SHOULDER BECAME SORE. ON 1/7/02 HE WENT TO E.R. AND WAS DIAGNOSED W ITH BURSITIS. HIS OWN DOCTOR DIAGNOSED THE SAME.TREATED WITH MEDICATION AND RESTRICTED DUTY.