A lot of us have the problem and it's because the proper steps weren't taken to install the brakes or debris and etc over time created the problem.
Here's a video on the fix:
The above is very through, however, I just took the wheels off and used brake cleaner to clean the brakes and sprayed a bit on front and rear of the calipers which included part of the rotors. Should be safe too do and I've had no issues. My squeal isn't as loud but it's still there but that's the best I could do without taking dissembling everything. I have not tried taking it to the dealer... well just because I don't like anyone but myself driving it. Figured if it was still an annoyance that the next time I got a tire rotation that I'd tell them to look into it.