Hey JR - just read your blog as I've got the same and had pretty much the same experiences.
A year ago I twisted out of a position and really hurt my lower back. I initially went to my GP who told me I had pulled a muscle and prescribed me some muscle relaxants. I was still suffering so I went to a chiropratic clinic. I spend hundreds, gave up running and pole fitness (as this always agrevated my back), however I was still getting a bad back periodically. I decided not to go back and subsequently tried sports masssage therapy. He gave started with deep tissue massage followed by use of a TENS machine. At first I thought I was onto a winner, he but after a few weeks the pain returned, it was also costing me a fortune. So, I stopped that. The pain got so bad that I returned to my GP, he referred me to an Osteopath. I've only had one visit so far (as it's NHS, at least he's not in it for taking my money!!). He's pretty confident that I have an SI joint injury and started by giving my acupuncture. This did nothing to ease the pain (he wasn't sure it would do but has to do it as process of elimination). The next step is for me to have an Wikipedia reference-linkMRI scan and it's highly likely that I will need a steriod injection in my back. Have you been offered anything like this?? It may be worth investigating.
I hope thing work out for you.