Wow this past hour I've been taking notes on Mark Prior's delivery and comparing it to my own. I finally found a huge breakthrough in my mechanics and why I used to have arm problems. I found out that when I broke my hands instead of pushing towards homeplate I kind of swung my body around. I found this was because I was trying to throw harder but was only hurting myself and causing my front shoulder to fly open and my arm to drag. I strongly recommend any younger guys on this site to do as I have done and study other pitcher's mechanics and compare them to yours. You don't have to change yours to be exactly like theirs but try to incorporate things into your delivery. I feel great!
Original Post