first off, chew...no i'm not confused, but i did word things wrong, so sorry bout that..i worked in a tire shop for a few years so i do know a thing or two about tires, more then most people.
at any rate, the rotor thing...if there was a prob with the rotors then i think you would have noticed with the brake job, or informed if you had someone else do them. you can try to clean the area out a bit to make sure there isn't any dirt that is rubbing, but that sound generally is more of a grind then a screech.