Far too many doctors, even neurologists, don't recognize that foot pain that is burning or stabbing in nature might represent small-fiber length-depedndent peripheral neuropathy--and standard nerve conduction studies will not pick up on this, as they can only measure the functin of larger, myelinated nerves.

There are certain types of tests, such as quantitative sensory testing and various autonomic tests, which might be able to pick this up, but the current gold standard is skin biopsy for intraepidermal small nerve fiber density/condition analysis (only done at about eight centers in the US, but Hopkins has a program to which samples can be sent and analyzed by them).

Take at look at:

http://www.thecni.org/reviews/13-2-p07-treihaft.htm