Today I took my mechanic for a drive and they took out a part from rear brakes, it was rusty and he told me it was some sort of cover. I couldn't get what it was but rumbling sound was from that part and now it's gone.
Circular spinning sound still exist but I'll drive for a while and expect the noise to disappear. Otherwise I'll check in with another mechanic/dealership to find out the source of the noise.
