What Causes Pain Under The Skin Of Foot Radiating Towards Ankle?

I have burning type pain "under the skin and not sensitive to the touch" that radiates from the top of my foot (starting at base of my toes) thru the angle of foot and ankle....It comes in waves, again not sensitive to the touch....but the affected area appears to be moving from my toes back toward my ankle....No trauma and it is only in one foot....when pain comes it is at a 5-6 level...