Sorry no one has been along yet to offer insight. I wish I could help - my journey in the neurological world started back in 1998 with cervical problems, but it sounds like they've screened your neck with an MRI - hopefully that's ruled out.

Someone should be along in a bit with more experience in PN than I - still in the learning process here. It's good that you are having blood work done; my neuro took 15 vials at one point to screen for a number of problems from Lyme to heavy metals to thyroid.

Just know you are not alone.