When I do a lot of pressure flaking on tough materials I get a pain in my left shoulder. I'm right handed, so its happening on the arm that I hold the point with. I can slow it down a bit if I concentrate on bracing my left hand on my knee and use an Ishi stick instead of a short pressure flaker. Once it happens Advil/Ibuprofen helps with the swelling and a tensor bandage can take some of the pressure of the shoulder. But it doesn't really go away until I take a break from knapping for a few days.

