Welcome to NeuroTalk...

I have a few questions:

How old are you? Do you take statin drugs for cholesterol or have had antibiotics from fluoroquinolone family in the recent past, or Flagyl (metronidazole).

Have you been evaluated for MS? Had an MRI to exclude it?

Have you had your B12 measured and is it over 400pg/ml?
Vit D also...? goal for that is 50.

Do you know your A1C? Do you drink alcohol regularly?
Do you get vaccines?

Have you considered a food intolerance like gluten intolerance?
Also nightshades can be problematic for some people.

Are you exposed to toxins, pesticides or fungicides in your job or hobbies? Solvents? Like cleaning up greasy oily hands?

Did your doctor test you for a heavy metal load? (mercury, lead, cadmium, arsenic? )

PN may be from some environmental assault or exposure.
Or it can be from a metabolic process going on in your body (autoimmune, diabetes, bone marrow disorders)
Or compressive issues in the spine pinching nerves.
Or it can be hereditary...for which there is not much you can do but avoid triggers listed for it. (do you have relatives with nerve damage? )

I'll be leaving Fri am for a long hiatus here of 2 months, so if you can answer before Thurs night, I can possibly point you in a direction to further investigate. Not all doctors do all the tests available, unfortunately.