When I drive very slowly I can hear an intermittent noise from my rear passenger side brakes

I drive a Kia Spectra. When I drive very slowly I can hear an intermittent noise from my rear passenger side brakes. I took the tire off and when I turn the rotor by hand it makes a noise at the same spot on the rotor like there is a high spot on the rotor. I had the rear rotors ground and put new brake pads on. The car still makes this sound when I turn the rotor by hand and when I drive slowly it makes a swoshing sound. At higher speeds I do not hear anything. What would cause this? Yesterday I noticed the tire was worn on the outside. May be coinsidence since this is the oldest tire on the car. Any ideas?