Massage therapy can be helpful if it's aggressive enough, not the surface 'feelgood' rubdown. Rolfing is another option, but requires a minimum number of sessions (six, I think). Chiropractors can help if they understand the underlying medical problem. but should always be willing to refer to a doctor or phsyical therapist when they don't.
For example, I went to a chiropractor for years for neck and shoulder pain. After an adjustment, I'd be ok for awhile, but then the pain would return. I finally went to an orthopedic surgeon who correctly diagnosed a nerve damage problem from and old motorcycle accident (I'm a 'winger', the scapula sticks out from the ribcage due to weak muscles on account of the nerve damage). Anyway long story short a physical therpist showed me exercises to do that substantially reduced the pain.
Mike, I assume you're talking about lower back pain? A big gut (yeah, I've got one too) aggravates the problem, especially with a previous injury. Ask your doctor, he'll tell you the same thing.