What Causes Burning Sensation Under The Feet?

I started having burning sensation under my feet since August 2010. I tried all possible remedies, asked all doctors known to me, took Evitamen. B12 tablets. I observed that eating spicy food aggravates the problem. Some times it escalates to my calf musles also. Iam 60 year old female with B.P. problem.mild heart dysfunction. Not diabetic. What may be the cause? Pl. help me.