Push your palms together as if you are going to squish something in your hand. Do you feel the sharp pain while doing that? If so then you probably have what I get on and off, and that is pec tendonitis. I have switched from heavy, to light, to you name it. I found that not bringing sets to failure and not maxing often at all really have eliminated the majority of the issue. Slow grinders flare the issue up immediately for me. Hope this helps to some degree.