So it turns out all my inside pads were worn out while the outside ones were half worn and appeared to be okay.
The Rear Right disk was touching on the dust shield. Rear disks were also warped.
Yesterday, my Front Right wheel started making a loud gring noise. Turns out the inside pad's backing (metal) plate was so worn that it broke in half.
So I had the pads and disks replaced today.
Can you guys understand why the inside pads would be completely worn while the outside ones remained half worn, on all 4 wheels?