2007 Hyundai Sonata Squeal type noise sometimes

My car has recently (maybe a month or so) started making noise. Its a squealing type noise, and isnt there always, so its hard for me to take someplace, since its not making that noise then. It started during the morning time when I drive to work. Again, its not a noise which starts as soon as the engine starts, and is fairly light, but its there.
It comes and goes, with no particular influence that I've noticed. One thing I noticed was that the noise momentarily stops when I press brakes, but when I release them, it starts again when I accelerate or step back on gas. I recently had brake pads installed on my front disc brakes, and I think the mechanic also resurfaced the rotors, so I am thinking that could be an issue, but not sure whey would it stop making noise when I step on brakes, shouldn't it increase if rotors were the problem? Anyways, I am completely stumped by this, since I am not sure of the problem, and have taken it to dealership, but it didnt make the sound then. If you are aware of the solution, please suggest some cost effective and lasting/permanent solution/fix for this.