Sorry about the back pain. I would add chiropractic care to the list of options. Not all chiropractors are the same, so it's worth researching the various methods and then interviewing a potential chiropractor about his approach. If the issue is that the back is out of alignment then chiropractors can really help. For things like slipped or broken disks, chiropractors may not be able to treat. A good one should know when the problem is out of his area of expertise.
I went to a really good, highly recommended one for quite some time years ago and, for me, it never really brought consistent results that I could see. I know for some it can be helpful though. Thanks for the suggestion.