Hey guys i`ve been having this tired muscle/pinching uncomfortableness in my right shoulder/trapezius for like a month now.. it feels like its sore or something... I`ve been punching my heavy bag, so its the right straight i guess that is causing this pain... i`m not sure why.. could this be inproper mechanics? i recently moved from 80 pound to 130 pound bag.. i weight 160 pounds could it be cause because of the heavyness of the new bag? what do you guys think???