EE WAS BAGGING & STACKING PROCESSED LIMESTONE ON A PALLET WHICH WAS SITUATED ON A HYDRAULIC PALLET JACK LEVELER. HIS BACK WAS SORE AT THE END OF THE SHIFT. THE FOLLOWING DAY HE FELT FINE WHEN HE ARRIVED AT WORK. HE PROCEEDED TO BAG A FEW PALLETS & THEN FELT A SHARP PAIN IN HIS BACK/SHOULDER AREA.