It is very possible you just have mechanical issues in your feet.

This is very common, and you were wise to get that evaluated.

I would try Salonpas patches on that tendon, and across your arch. They work well for me for my sesamoiditis. It sounds like you have tendonitis and the anti-inflammatory actions of the patches may give you relief.
Try the original ones...not the others.
http://www.walgreens.com/store/c/salonpas-pain-relief-patches-topical-analgesic2.56-in.-x-1.65-in./ID=prod4526-product?ext=gooMedicines_ampersand_Treatments_PLA_ Hot_ampersand_Cold_Therapy_prod4526_pla&adtype={ad type}&kpid=prod4526&sst=2c7bbf3f-0bc9-a1c8-d226-00004f5d8f2a

They are not expensive and are surprisingly effective.
Patches like this can be very effective when you have a specific target to put them over. And you do.

When a person has PN....that will hurt in some way even when there is no motion. Pain that only seems prominent with movement is often mechanical and inflammatory. Pain all the time can be from some internal process (autoimmune) and/or inflammatory/metabolic issues which are systemic.