unless it is something drastically severe, Hitman is most likely on the money... the small brake switch, located on the underside of the brake pedal, on the "plate" of metal that hangs down, and stops the brake pedal from traveling any further. It is an "insert and twist" type of securing mechanism.. those can break on the inside.. lean in on the floorboard, and find that switch, see if it feels flimsy, or cracked, or just popped out of position..
Ray