Heat Intolerance Treatment Heat Intolerance!?

Heat Intolerance!? - heat intolerance treatment

I suffer from an intolerance to heat. I try to find due to medical reasons. I know it's not drying out or too much sun. I drink tons of water and because they avoid the heat is not good, you avoid the sun whenever possible. What has happened for years and has only worsened.

No idea what could be causing this?