EMPLOYEE BENT DOWN TO PICK UP A ROLL OF PLASTIC WEIGHING 47 LB TO CARRY APPROX 40 FT TO STAGE FOR WRAPPER. WHEN SHE LIFTED UP THE ROLL OF PLASTIC SHE FELT A PAIN IN HER LEFT SHOULDER ON LEFT S IDE OF CHEST. DIAGNOSIS WAS MUSCLE STRAIN. SHE IS CURRENTLY ON LIGHT DUTY WORK.