Heat Sensation In Upper Back Why, When I'm Working Do I Get A Sensation Of Prickly Heat?

Why, when i'm working do i get a sensation of prickly heat? - heat sensation in upper back

I had a wave of heat on my face before, but it is different, do not develop visible symptoms. It feels so red-hot needles stuck in my back, neck, shoulders and arms! Everything I do is constantly biting, comes in waves, building the intensity and is unbearable!