rear wheel making sounds when brakes

first of, my bad if am not in the right place to ask the question. (this is my first time posting lol)
Question: Ive been hearing this sound on my car when i put brakes on. from rear wheel, drivers side. its not a squeaky sound but more like a thumping sound. sounds like tire is rubbing off something but only when i brake. i tried to check couldnt find anything. its been 2 weeks and today the same tire gone flat.i took out the tire and saw it was rubbed off from inside. ill post a pic too if anyone wanna see. i dont know wat it is if any of you guys have the same prblm or know about it plz let me know. thanks. ps. new brakes and rotors installed 2 months ago
car is not dropped (yet) lol. am thinking alignment or wheel bearing?? still dont know