Let me echo Eileen's post about going to a physical therapist. My ENT (who was wonderful in every other way) blew me off on this one and told me I didn't need PT after a radical neck dissection. About 4-5 weeks later I could barely lift my left arm.
I've been going to a PT for about five weeks now, and it has made a world of difference. I'm still not where I want to be, but my pain level is way down... Get thee to a PT!! Plus it feels good when they massage your neck and shoulders...
Eric