The last time I had my brakes done, my car developed a high pitched whine whenever I turned left. Didn't do it when parked, didn't matter if brakes were applied or not. I thought it was power steering related, so I took it back to the guys who did the brakes. Stumped them as well. They confirmed they could hear the noise, but advised me my power steering was fine and no apparent brake issues. I asked what I should do, and the guy actually told me 'learn to live with it'. Which I tried to do for about two weeks, until the squealing sound I got every time I went through the drive-thru was about to drive me nuts.

I was absolutely convinced the sound was coming from my left front tire, so I jacked the truck up and took the tire off and gave the hub a spin with the wheel cranked all the way over. Brakes were fine. Realized the sound was actually coming from the opposite side. Went over to that side, and brake pads and caliper looked fine. But I could tell the squeal was coming from behind the caliper, so I pried it off and looked around. Turns out there was a tab on the pad retaining clips that wasn't bent all the way down, and on a hard left turn, it would briefly graze the rotor, making the squealing sound. The solution was to bend it down all the way, and the problem went away forever.

So as with Ray's thoughts, I'd have someone look closer at the brakes, regardless of the fact that they were just done.