Browsing the forums I noticed a thread on dealing with neck and shoulder pain from playing bass guitar. It's something that seems to affect a lot of bass players, myself included.
I recently blogged about my experiences and how I got rid of the pain. It was actually quite simple once I figured it out. I thought it might be useful to others in the same situation, you can read the post here; http://whatisbest.info/?p=189
Hope it helps!