I hurt my upper back last night while doing dumbbell shoulder presses. Today, the area is sore and is incapable of supporting much (if any) weight. Any ideas what I did to it?
You may have used too much weight on the presses. Sometimes the body needs a rest. Are you doing these daily? You should not work the same muscle group every day. Alternate between days doing different workouts. I like to recommend the upper body work out every other day, and the lower body workouts the opposite to give the muscles a rest. Sometime when we are a little under the weather our body is telling us not to over do take it easy a day or so. Give it a couple days of rest before working out again. Sounds like a pulled muscle.