So about a week ago I started getting a weird groaning/rubbing noise coming from the rear of the car during slow turns and u turns. Occasionally would hear/feel it on the interstate as well. Sounds like it's coming from the right rear of the car, and it would only do it once the car has been driven for a while (15+ mins on the freeway)

Well about 3 days ago I caught a flat (probably unrelated, tie developed a slow leak a while ago) and had to jack the car up to put the spare on, and also to get the new tire put on. Now ever since then, the low speed groaning and rubbing has decreased, but now the wheel will run the wheel well on anything over aa slight dip in the road, and the right rear is sitting roughly an inch lower than the left rear. What could this be?

 

First thing to do would be to check the obvious: broken or damaged shock or suspension component.
Was the flat tire on the same corner that the noise is coming from?

Craig