Brother, you have my sympathy. You've been dealing with this a long time, spent a lot of time and money with no cure in sight.

Have you tried chiropractic? It helped me once. I've never had acupuncture, but many swear by it. The Eastern energy modalities might help, and your skin doesn't have to be touched. If you can stand light touch along the meridians, shiatsu combines Traditional Chinese Medicine with Western medicine, in that many of the trigger points are also tsubo (points) for accessing the energy meridians. the Bladder meridian runs from the medial orbit of the eye across the scalp and down the back into the leg and foot. Shiatsu helped a cousin a couple of years ago who had similar burning pain in the back.

MrsD's list of possibilities is quite extensive. Herpes gets in the body and never ever leaves; as MrsD reiterated, it hibernates in ganglia and when the body is weakened it can awaken and wreak havoc. And with all the throat problems, you were certainly weakened. All the drugs may be butting heads with one another.

For a decade I had the burning sensation in mid-back region after an industrial accident. Not as intense as yours, probably-- I could still function. The only thing that gave me any relief, every night I had my wife (100# or so) walk up and down my back; it would make the cracking sound and for a few hours I'd have relief. BTW, the cracking sound when someone cracks your back is said to be nitrogen bubbles in vertebra popping. Some people get an audible "pop" in the shoulders when they rotate their arms also.

I hope you find the cause, and it can be cured.