Rear brakes grinding sound

Hey, I started hearing a grinding sound in rear drivers side brake area about a week ago, both when applying brakes and even a bit when not applying them. So I inspected the rotors and pads and pads. Definitely needed replacing. Also, there will indentations on rotors. Do not think rotors had ever been replaced.

I removed both rear rotors and pads today and replaced (which was not fun for a while because of the caliper brackets bolts being stuck). Anyway, put it all back together and did small test run and I am still hearing grinding noise when I am coasting. Not so much at all when applying brakes. Could something like the bushings, or slide bolts in the caliper be in need of replacing too? Or is there something that is causing this grinding sound?

thanks.
Elijah