Two doctors said it COULD be my hypothyroid after going through my tests and stuff. So then I began to research it and low and behold I found that hypothyroid CAN cause pn. Also, while it is not definitive, my numb spots on the back of my heels improved after getting on thyroid medication.

So far my pn has not progressed but stayed the same, if somewhat improved since supplements and dessicated thyroid meds.

Could there be something else that caused it? Sure, but right now neither myself or my doctors would know what, and I have stopped wondering what can cause it and just focus on how to treat it.

Edit to add: go to http://www.stopthethyroidmadness.com/ that place is amazing.