I think your body already answered the question, but I'll give you my thoughts. There is nothing walking this earth that requires the need of a 70# bow. Certainly not a whitetail deer. You've already had shoulder surgery and I would think that you don't wish to repeat the process, so a lower poundage is what I'd recommend.
You don't necesarily have to give up more than a couple fps from the bow if you'd drop to 60# or so. You'd necessarily have to shoot a lighter spined arrow which could, depending on which one you choose, would be comparably lighter in weight so your bow could shoot at the same speed. Yes, you'd be giving up some kinetic energy but almost any properly spined arrow for 60# or so is still heavy enough to give good penetration on deer, and even heavier game.
So I'd say drop some weight so you can at least draw the bow.
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