Have you thought of a Chiropractor? I know... most people don't believe in them, but for what you are experiencing, it sounds like it might help.

For example, I was having problems with my back and movement in the neck. Went to the Chiro, fixed me up well enough to do a full shoulder check while driving. Hmmm now that I think about it, I have fewer people honking at me when I change lanes. Coincidence? I think not! ;-)