Is heated up bleach dangerous? I put my electric flattop oven on self cleaning. This heated up the top of the oven. I then bleached the flattop. The bleach steamed up and made it nearly impossible to breath. The entire room is now unenterable due to the fumes. It is not merely a typical bleach smell. I can't breath when I am inside and my eyes are on fire.

Is there something about heating up bleach that is particularly dangerous?
Probably generated some chloramines by reaction between the hot bleach and proteins on the stove surfaces. There's no telling exactly which chloramines you created, as we have no idea what amines were on your stove top. However, these things can be quite nasty.
Open windows if possible, and leave home for several hours. Your eyes and lungs are giving you important warnings. Heed them.