Rear brake noise goes off when brakes applied

My rear brake starts to give out some noise after few minutes when I start driving the car and then when I apply the brakes the noise goes off, and comes in again when I release the brakes. The noise tends to be louder at lower speed and goes off at higher speed (only some times).
Really annoyed with the noise, plus I replaced the brake pads and also got my rotors re-surfaced. And the the noise started to come after say one month of replacement of the pads. And only one side (rear left side) give this annoying noise.
Really need help.