Is it safe to use non stick cookware over a flame? I have recently started to learn how to cook. Whenever I am trying to make a chapati or to cook a vegetable, I start experiencing an acute headache, most likely because of the steam or maybe the flame in burner gas stove. I am using non stick cookware. Can this be the reason for getting the headaches?
Are you using non-stick cookware? 

Beware because there is a well-documented medical effect caused by the fumes released when various non-stick components are heated starting at about 300 °F (149 °C) and beyond.

Polymer fume fever

You should always have something in a non-stick pan when it is over a flame.