SJ69

My trapezius muscle on my left side has been cramped for over 3 months now, I have constant pain every day, some days bad, some not so bad, but it's always there, it never goes. I've been to the Doc twice for this, the first time he gave me 4 injections of lidocaine, the next time another four shots but double the concentration. The injections helped somewhat (about 50%). The idea is that a numb muscle cannot contract thus the spasm is released. I don't think I'm injured, I think (and does the doc) that stress caused the cramps and they're just stubborn.
Is there any stretch I can do to alleviate the cramps?

"I don't like small cars or real big women, but somehow I always find myself in 'em" - KR