Coach,
Sorry about your condition, it is very frustrating to look for proper diagnosis.

You mentioned bulging discs at C level and at L level as well ,I think. I can see how this could cause some neuropathy. I have bulging C 6 - 7, and it has contributed to radiculopathy with pins and needles numbness and weakness in left arm.

You mentioned arthritis. Is it OA of the spine you have?
That in itself can be very painful. And with bulging discs and nerve compression from this both at C level and L level, I can imagine you must have a lot of pain. And when you add on SFN, OHHH then there must be pain.

Do you have the SFN as a burning pain all over? ---I do.

I have both OA and RA, and my rheumatologist said my SFN has come from that. I also have vasculitis, so that could be a cause.

Are you taking any meds for pain? A lot of pain meds has side effects as dry mouth, dry eyes, constipation etc.
Sometimes the doctor orders Antiseizure med like Lyrica to treat the nerve pain from neuropathy. Antidepressant is also used in combination to above. But you might already know this.

I wish you all the best for the spinal surgery.

Synnove