Do you get to sleep and the pain wakes you up, or is it just more intense at night and prevents you from getting to sleep?
All sorts of pain-y things, I think, get worse at night, and I think some of that is because you don't have other stuff to distract you. I'm sure there's a physiological reason as well.
My mom has tendinitis in her elbow and neck, and she puts a heating pad on the one on her neck (the elbow one isn't quite so bad) before bed, but doesn't actually sleep with it on.