Creaking sound

[StudioWizard]

My 2005 2.5i is starting to make a creaking sound coming from somewhere in the back of the car. I started noticing it after I had the stabilizer bars repaired in the engine compartment. It's possible the car was a little loosey-goosey and now that it's tighter, other loose parts are showing up.

I'm sure something just needs to be tightened. Any thoughts on how to go about figuring out what it is and how to fix it?

Thanks!