Josh-
It's called a rotator cuff, and it's a mother focker to come back from. Do like Brad says, go see the doc, and make sure you tell them it happened at work. Don't fukc around with this, I'm officially retired in about 3 more weeks, due to my shoulder injury. Well not really retired, but I won't be a plumber any longer, gotta get vocational rehabilitation.
DO NOT FOCK AROUND WITH THIS. YOU WILL GET OLD.