I've heard that alternating the heat and cold is good - the heat relaxes the muscles, and then the cold relieves the inflammation. Not sure how scientific that is, but I don't think you'll harm anything either way, so long as you don't keep either one on for more than 10-15 min at a time.
Ummmm.... Other than that, you probably know the usual drill - good posture when sitting/standing... sleep with a pillow between your knees...belly belt might be a good idea... hmmm, what else.... I think doing some gentle stretches where you are on your hands and knees and then arch your back up, and then relax (don't droop, just relax) can help somewhat.

Hope you get some relief soon, hon!