HOT headlight Switch? Don't know why

Do you have stock headlights or super bright?

I agree that most likely (short is a short) your connections on the headlight switch, the high low beam switch and the bulkhead connectors and at the headlights themselves are corroded and you have a bunch of resistance over the headlight itself.

Most likely you will need to replace the plastic terminal holders in a few of those locations.

May even need to replace some of the terminals as when they get hot enough they loose temper and can never bite hard enough in the future