Sometimes when im working I get a pain like a burning feeling at the top of my back just below my neck. Whats the cause of this?

Strain. Do you work at a desk or on a computer? Do you typically have your head down when you work? This is most likely due to overworked muscles that help suspend your head at the tip of your spine. The human head weighs about 9 pounds(4.5 kg). Those muscles will begin to complain after a while. Periodically stop and stretch, lean your head back and relax. Also change the position of your screen.