I have been experiencing shoulder and upper arm pain in my left arm daily for the last year after a sports injury. Its moderate pain. Nothing broken. But, ive lost all strength and it feels like it wants to snap in half. There are certain spots I can press along the shoulder and length of the radial nerve and pain will shoot out like energy bolts and then the arm feels fine for a while. I am Dave, male,46, 6 0,275 lbs. what is happenning?