How come I get headaches whenever I have my car heater on?

Car induced headache. Consider a carbon monoxide leak into your car. Drive with a window open and have a check for carbon monoxide levels. Excessive heat in the car can contribute to headaches headache especially if the windows are closed and there is a lot of up and down movement of the car. Sit in the front seat.
Carbon Monoxide??? Unique. I would get the car checked out asap. Do other passengers have similar reactions while sitting in your car? This could be dangerous.