What Causes Burning Sensation In The Feet?

Hi, I’m 29 years old and for the last 6 years I have been experiencing burning sensation in my feet and I have visited the doctors office on many occasions and each time they provided me with a different story. First told me that I was stressed out and second time he mentioned I had restless leg syndrome and prescribed me pain killer, I was happy for the first week and later the pain was back then they prescribed me vicodin, it worked for a while then I was again in pain. I stopped the medication due to the side effects.

Till today, I am suffering from this burning sensation and mostly it occurs when I lay in bed and I cannot sleep for hours and the longer I stay in bed the burning sensation increased in intensity. The only solution that so far that sometimes it works by drinking 5 cups of cold water with vitamin B12 before sleeping but yet have to wake up to use the restroom. I would really appreciate to know the causes of this condition and if there are cure for this condition???

Thanks