I have the same problem. I did two things that help pretty much.
1. try and start recognize when you are tensing your shoulders, and then deliberatly relax them...even if you have to sneak off to deep breath for five minutes or so.
2. I bought a micorwaveable heading pad that specifically fits around your neck and shoulders. I'm in the US and I bought it at my grocery store, and I think Wal-Mart sells them. I put one on, and GENTLY massage, rub my neck while it is on. Then I fall alseep with the hot pad, and the heat fades as you sleep. That has helped me tremendously.
It cut my tension headaches in half. :)
