Have you looked up medial plantar nerve entrapment?

http://www.merck.com/mmpe/sec04/ch043/ch043k.html

also showing source:
http://en.wikipedia.org/wiki/File:Gray834.svg
http://en.wikipedia.org/wiki/Medial_plantar_nerve

http://www.chiroweb.com/mpacms/dc/article.php?id=41649
This is a very good article: it describes Tinel's sign. Can you get that when following the directions?

I can't recall if you have seen a good podiatrist? The reason I ask is my son had a terrible pain in his foot when he started college and had to walk long distances, which was traced to an overpronation problem on that side. The orthotics that were made for him corrected it. He had x-rays and other tests, to rule out other problems. Prior to the fix he was very picky in selecting shoes ... I can recall spending hours trying on shoes with him when he was younger! Now he is totally normal in this regard.