Thing is... you've got such a confounding list of symptoms... There could be so many causes for many o them. I have no doubt there are many people here who've experienced one or some of them (I've got several myself) but the big picture is perplexing -- especially with all the negative testing. I'm not surprised the doctors are baffled as well. Medicine doesn't know it all yet by a looong way.

Relieving them -- especially those that are neurological (which is most) -- depends at least in part (if not all) on the cause, and that's the snafu. Those of us with peripheral neuropathy (PN), for example, just have to live with the numbness, tingling, occasional shooting pains/needle jabs/shocks. For some (like me), the burning pain can be alleviated with supplements (R-lipoic acid*, B12, B1/benfotiamine, D3, magnesium, others). I seem to be thirsty all the time too, so I just keep a jar/bottle of water handy while I'm awake.

*the only one that helps me with burning of PN

Oddly, I test negative for diabetes too, yet my symptoms respond as if I were diabetic, so I do much better going carb-free (no sugars or starches except veggies & non-juicy fruits). Experts (heads of neuro depts at local medical ctrs) have no explanation except, "We don't know it all."

It also occurs to me that at least some of it may be dietary, as cracked as that may seem. This can occur at any time in life, even though one has eaten things without repercussions previously. Have you ever tried going gluten-free, sugar-free, or dairy free. Some people are also very sensitive to things like nightshades (tomatoes, potatoes, all kinds of peppers, eggplant, some herbs & spices, etc.) Such a trial would have to be absolute (no cheating) and for at least 3-6 months to know for sure. If it doesn't help by then, at least you can rule those things out and enjoy to heart's content.

Doc