Ok you automotive wizards. Whoever helps out gets free cyberhugs.

Background - I had a leaky valve stem and took my car to Walmart to fix it. (I know. Questionable call.) They didnt have a TPMS sensor so they just stuck a normal valvestem in since they said my old one was bad. Shortly afterwards my car started shaking and gradually got worse. I had a TPMS sensor put it and I replaced the front rotors and pads and that solved 80% of the problem.

My current problem - My car still shakes slightly and there is a rubbing/grinding sound (not so much grinding though). Its hard to describe. It KINDA sounds like a really loud tire. Its actually not that loud though. lol. More of a low drone. I would upload a video but theres no way that anyone would be able to hear it over road noise and stuff. Anyways, I feel it more in the pedals than the steering wheel (I heard before steering wheel meant it was a front end problem and pedals meant it was a rear end problem but I don't know how true that is.) Braking does NOT make it worse. Acceleration seems to be slowed quite a bit. The symptoms remain constant when the car is in neutral. Higher speeds make it worse.

So -
-slight shake
-rubbing sound
-gets worse at higher speeds
-braking does NOT make it worse

My thoughts - Wheel bearings or rear brakes. Or maybe alignment or tire balance issues.

Any ideas? The car has 86k miles btw.