So tonight I'm doing my typical saturday back workout which consists of deadlift's, row's, ect. I'm working up to a 4x5x225lbs on my deadlift by ramping up weight and doing 2 reps each. I'm on 185lbs, which is the second to last warm up set I do, and complete the 2 reps rather easy, just like normal. Immediately after, I go over to do a warm up set of barbell rows at 95lbs. I can only get 4 reps before I have to drop the weight because of a stinging pain in my right shoulder. At this point I'm confused because nothing felt bad during those 2 reps at 185. I went and tried to do a pull up and that hurt as well with the same type of pain. I grabbed 10-20lb dumbells and did all sorts of movements (frontal raises, lateral raises, press, ect) to see if that hurt and felt no pain at all. It didn't even hurt when I did db rows. Has anyone ever had anything like this happen to them? It's really bothering me because I couldn't complete my workout, I don't know what happened, and if it continues, how to fix it.
Sorry for the length, I wanted to be as descriptive as possible.