Get your shocks replaced. Seriously. You are all tensed up. Trying to push that bow at the target while your pulling it the other way, then holding that position for a count. You are all tensed up and rigid. Allow your body to go with the flow. Try loosening up, smoothing out your shot sequence to more of a rhythmic motion, don't stop, make it all one smooth continuos motion. Bend the bow arm, don't try to draw back towards your ear.
Then research all the bicep/tricep/chest/and back stretches you can find, warm up your body, and do 'em. Tendonitis can be reversed if you don't wait until you have scar tissue all around the injury site, and, DON'T CONTINUE TO DO WHAT CAUSES HARM!!!!