Some symptoms like other here sound to me like some kind of a allergic reaction. Did anything in your life routine change a year ago(food/location/job/etc)?

A deep(as if in the spine) center of the back itch(that cannot be satisfied by scratching) is one of my hay fever full on attack symptoms. Those are accompanied by numbness on the scalp w/itching there and surface spots of itching all over, wheezing, red face, itching of the roof of the mouth and the usual sneezing and runny nose. It all goes away after taking Benadril or other over the counter meds.

My PN symptoms are nothing like my allergy symptoms, isolated to my feet(so far), so no help to you there.