Is this a rotator cuff injury?

i am a pitcher for a college baseball team. today during warm ups the team was doing a long-toss drill. after my third or fourth toss, i felt a lot of pain all over the top of my shoulder during the downward thrust of the throw. after just two more throws, i could barely even rotate my arm in a throwing motion. needless to say i am very worried that something is seriously wrong and i need some sort of surgery. the problem i am having is that i cannot pinpoint the pain on my shoulder. i can press as hard as i want on the shoulder and it causes me no discomfort. it is only when i throw a baseball or do any physical activity that puts stress on that part of my arm. so if anyone (preferably a pitcher who has had an injury like this before) can give me any advice on this matter, maybe let me know if i should go to a doctor, or just wait it out and see if it gets any better, that would really help me a lot.