Brake lights stay on when vehicle is off, no one touching brake? Hazards stay on...?

My brakes in my 1996 Chevy Astro van stay on when no one is even in the vehicle, no light switches are on. And on the column, when i push down on the hazard switch, it makes a buzzing sound like when u switch the key from off to accessory. and now one of my turn signals dont work and the hazards are staying on, not flashing. like on the dash the turn signals are just lit up, not flashing.