I have had a left shoulder reconstructed due to three dislocations (football). I shoot right handed, My bow is set at 67# and I use to experance shoulder fatigue as well. I was shooting at a 3-D target range one day and this older fella, late 50's-early 60's, come up to me and tells me he could make my left shoulder stop hurting when I shoot. Now since I hadn't complained about my shoulder, I asked him how he knew my shoulder was even hurting to start with. I can't remember his reply, I don't I think it's what he said, but instead how he said it that got my attention. So I ask him to please tell me what I could do. He told me he had been whatching me shoot for a while and noticed that I would raise my left shoulder during my draw. He explained that by doing that, I was depending on the muscles in my shoulder for all the support needed to hold my bow. "DROP THE SHOULDER", he told me! The old wise man said that by dropping my left shoulder I would keep the ball of my shoulder in tact with the joint. Picture two boards butted together, then two boards put togther but instead of butting them up end to end, lie one just on top of the other. Now imagine pushing on the opposite end of the boards and see which moves and which won't.

So if you haven't tried this, then my advise is to drop your shoulder. If you are raising you shoulder like I use to, and I'm guessing you are, the you'll be amazed at the difference this slight adjustment to form will make. Remember, you want bone on bone. If you feel that fatigue at full draw, drop you shoulder down....instant relief! I hope that maybe this helps! Good Luck!