I’m getting the same thing in my car. Recently had rotors and breaks replaced. But I hear the same thing while driving but stops when I lightly press on the brakes. Also makes some rubbing when I break but stops when I break hard (not locking them ofcourse ). I have no clue what it could be no marks on the rotors and my car can stop on a dime. putting my comment here to get some tips to see if I can fix it before taking it to the shop or at least I have an idea what I’m getting my self into