Bayerische Motoren-Werke

My brakes started making a squeal and sometimes a hiss when applying the brakes in reverse a few weeks ago. Now, the brakes squeal when coming to low speeds stops, not only reverse anymore. With my brother at the wheel, I was able verify that the squeal/hiss is coming from the right rear brake only.

My front and rear pads were changed at 45K by BMW last year April before my factory maintenance ended. Now at 55K, I can't fathom why I would need rear pads already, especially with the i drive saying fronts brakes 21,000 and rear brake 23,000 until service.

Any of you guys experienced similar? I'm going to the dealer Thursday to have them fix my coolant expansion tank and plan to mention the brakes.