I can definitely relate to you. I am also a 55 year old man, self employed. Last fall I developed a great sensitivity to chemical odors, then insomnia, then increasing pain starting in the back and slowly developing elsewhere. I busted my savings going to doctors - three trips to Mayo Clinic, two MRIs. a DT scan, etc.. On the third trip one doctor sneered at me and told me, "Nobody ever died of pain. Just go home and get over it." Another doctor the next day smiled at me and said, "Well, at least we now know what's not wrong with you." Then he told me to go to a psychologist who would soon cure my hypochondria. I actually did see a psychologist who gave me the straight scoop. He said upfront that my pain was genuine, real, physical pain and was not psychosomatic or the result of depression and that my medical doctors needed to get their act together (my words, not his).
After that my local doctor finally diagnosed me with fibromyalgia. At that point I had as good a medical education as he did about fibromyalgia and we have worked out a set of meds that have got me functioning again - a sleeping med and two meds for nerve pain. Now, although I have constant pain, my pain levels are around 2 or 3 during the day. Before they were 9 or 10 (I can definitely tell you that 10 totally disables you, as you probably know already).
My advice is to find something to at least relieve your pain. Tylenol and ibuprofin (Celebrex included) didn't touch my pain as it was nerve pain. If you can't sleep properly because of the pain, get a sleep med that works. There are a lot out there and I finally found a good sleep doc that got me back to eight hours a night (not high quality, but much better than the 0-4 hours I was getting).
Although it doesn't sound like you have fibromyalgia (it took a long time for the typical symptoms to develop in me) I would bet that at this point you probably have at least some form of autoimmune disorder.
Believe me, I know what you are going through. I am just now getting back to work and trying to avoid living off the government. 55 is much too young for us to have this happen.