EMPLOYEE WAS LIFTING UP A 3/4 INCH DRIVE AIR IMPACT WRENCH WHEN HE FELT AN INCREASING PAIN IN HIS LOWER BACK. EMPLOYEE WAITED UNTIL 5-11-00 TO SEE PHYSICIAN. THE EMPLOYEE WAS PRESCRIBED CELEBR EX 100 MG AND SENT TO PHYSICAL THERAPY. RE-EXAMINATION IN 3 WEEKS.