I started working the a concession stand at the State Fair of Texas 4 days ago, where thousands of people come every day for 24 days. I stand and walk and move around allot, and the center of my upper back started burning on the second. It is severe burning, along with the bottom of my feet burning. when I take breaks, and sit down the burning is still there. I work 12 to 13 hours a day. It stops when I go to bed at night. This is the fifth year I have worked it and I work it every day of the 24 days. I have never had this burning before. Do you know what it might be, or what might ease the burning?