Enough of your symptoms sound similar to mine as well, to be SFN. I also have restless leg syndrome, have ever since I was a little kid. I have hereditary neuropathy, so both SFN and large fiber. I am not sure if my pain is as bad as yours, I am on pain medication which allows me to be active, but driving is awful. Within about 15 minutes I get terrible pain in my back.
I also have the L4, L5 ruptured discs, had a laminectomy for sciatica in 2000.
It can be very difficult to get diagnosed and some people never get a satisfactory answer. My neurologists just said there was nothing they could do, good luck.
I hope that you get some answers. Does anyone in your family have PN?
Try to get a skin biopsy if you can.