The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
This is where I would start. Go to howmuchyoubench.net and buy the original SlingShot made by Mark Bell. It will help tremendously to re-establish your bench groove. Also work on releasing any tension in the soft tissues above and below the collarbone with a lacrosse ball or tennis ball or something like that. Lay on your chest on a plyo box and dig the ball into those tissues and move your arm around like you are doing a push up. Start there.