My rear tires are getting worn from the inside. I don't know whether the rubber bushes are worn-out or is something else. There is that clanging sound from the back. I tried wheel alignment many times but the problem still persist.
It is normal for tires to wear faster on the inside. When the alignment is done, the camber is set negative, so the tires lean slightly inward. They are typically more negative on the rear to help avoid oversteer.
As for the clank - under what conditions do you hear it? going over bumps, in turns, braking, accelerating? can you recreate this noise while the vehicle is parked? Can you jack up the vehicle and inspect to see if anything is physically broken?