I didn't know it at the time, but I pitched the first game of our season my junior year. It was cold and I was over throwing, I was supposed to be the stud pitcher that year.
The next day my arm was shot, I could not throw overhand at all, our idiot coach put me in left field, and I had to return the ball side armed, which still hurt.
Fifty years later, it's getting worse, and I learn I had a torn labrum. So, since I pitch nowadays at fantasy camp, I get it fixed (which is an odd surgery). I'm doing pretty well now, but my shoulder still has some deep pain and I can't throw like I did at 17. If you ever watch a major league pitcher in slow motion, the arm angles are bizarre.
And unnatural.