Deer902,
It doesn't matter that you can draw 70 pounds easily. As you stated, your work might be the main culprit causing the pain. But shooting high weight bows with the recoild and vibration just aggrivates it more, and will, in time need no root cause.
After being there and doing that, getting cortizone shots in the shoulders and elbows, I can honestly say it's a lot more fun shooting 55 and 60 pounds than it was 70. And there is no more pain other than the old age kind.
Think about it. You might have to bust your butt and abuse your body to make a living. You don't have to do the same with your hobbies. Hobbies are supposed to be fun.