Petra - sounds like you are ideally qualified to help me - I've found the Alexander Technique to be of help and I have found a fantastic physio who has done some craniosacral therapy and myofascial release, both of which have been some benefit.
Texasgal - I'm sorry to hear about your problems, it definitely sounds like we are two of a kind! There seems to be very little understanding of problems like ours - like you, I've pretty much been written off by the NHS, just told to take painkillers and get on with it! Easy to say, but not so easy to deal with when you are in pain all the time and it is interfering with every aspect of your life!
I still haven't found a magic solution to my problem - and I think I'm now resigned to accepting that there isn't one and that I will have to learn to live with the pain. But the good thing is that I feel I am managing it a bit better now - as I said, the Alexander Technique has been a godsend - it has improved my posture and has also helped me deal with the psychological effects of chronic pain. I feel a bit more in control of things now, rather than feeling the pain is controlling me. And I've found a great private physio, who uses a number of different techniques (mobilisation, myofascial release, craniosacral therapy, acupuncture, exercises) to help relieve my pain - this is only temporary, and only reduces the pain, rather than eliminates it, but its still something positive. She is the only physio who has really been able to help me though (and I've seen 4 others) so I think it does vary a lot between different practitioners. I've been very lucky to find such a good one!
I hope you can find something to make life more bearable - I know how horrible it is being in pain all the time, and it does drag you down. But don't give up the riding, whatever you do - I think us horsey people need this to keep our spirits up!!