Creaking from drivers rear after alignment
 

I went to get an alignment earlier this spring and after driving around with the windows down I noticed a creaking sound when accelerating and decelerating. It doesn't happen going over bumps, but it happens when you load or unload the car via accelerating/braking. It happens in reverse and in every other gear. I've unbolted the sway bar and that wasnt the noise. Someone said it might be something with the brakes, but I don't know what would have been messed with during the alignment.

Hopefully you guys can identify this sound.

Link to sound: https://youtu.be/9YryvNzk_9A