I began having burning pain around the back of my left heel several months ago. The skin is sore to the touch and the pain shots around the heel on both sides. The pain is burning but also like a sore from an injury but I have not injuried it. I have developed a large lump on the back of the heel that feels hard to the touch. In the last week, I have started to have the same problem in my right heel. I don't have the lump yet on the right side and the pain has receeded somewhat from the intenisity that it was at the onset. I am in my mid 50s and very active. What could this be from and what would be the treatment?