Rear tires screeching, worse in reverse

[Jdjig]

This just started today. Initially it happened going forward but it's even worse when going in reverse. Don't think it's the brakes since it doesn't happen during braking but it does sound like an issue with the rotors/break pad vs. the axle. It's only the rear tires.

 

[Jdjig]

SOLVED. I was able to remove a rock that was stuck in the dust cover of the rear passenger wheel rotor.