Why do my break lights stay on even when my cars off?

Its a 98 Honda Civic

The switch is either bad or sticking.

Is the brake pedal unusally low? That would activate the brake light switch. Check the brake fluid reservoir. The switch is adjustable but an awful thing to get at under the dash.

First, their BRAKE lights. Second are you sure their the brake lights or tails? If they are brake then you need a new brake light switch.

They are BRAKE lights.
Get your electrics checked out.