Miner operating frontloader clearing drifts.While turning steering wheel, he felt a spontanous pain (like a pinched nerve) in L. shoulder joint. There was no collision, jostling, or disruption in cab when this feeling occured. Miner waited until next morning, when he said it was still sore, taken to Doctor. Work restriction for 1 week and NSAID meds. given, to be re-eval. 3/18.