This is s very common problem and a easy fix. You need a new brake sensor or a combination of sensor/pads/rotors. As soon as you replace the sensor and what ever else your car needs the break light will go away on its own. This has happned to my twice. The first time it was just a sensor and a year later It came back ,but this time I needed new brake pads ,rotors ,and a new sensor.
If you take it to the dealership they might tell you that you need to upgrade your softwear wich is complete bs. I sugest you do it your self its not that hard, and there is plenty of DIY threads on the board.