squeaking from the rear

ggiwin

So I just noticed this since sunday night. I was driving to meet up with a friend last night and had noticed that my car was squeaking for some reason, pretty loud as well. I had my friend stand by the side of my car while I was parked and turned my wheel to the left and right. He said he could hear a squeaking sound coming from the rear. As we were leaving the plaza, the squeak got even worse. I was able to hear it as I was driving, even more pronounced as I went over a speed bump. When I was going on the offramp which curves around, I could hear the squeaking as well. In my head I was thinking might be power steering fluid as I was running pretty low, around cold minimum.

Next day, I decided to take it to the shop to see what they could do. As I was driving there, I could hear the rear squeaking as I was going down the street. Once I got it to the shop, the owner said he couldn't figure out what was causing it. I had them flush and refill the power steering fluid. Initially, I thought it did the job but it came back again several hours later. Now I'm kind of lost on what to do.

**Things that I have done to the car**
Lowered on swift springs for about 20k miles
using SPL rear camber arms
Replaced power steering fluid
Sounds like this, EE ER EE ER EE ER lol.. like a bed with old springs

TLDR rear of car squeaking loudly, do not know why. Any idea of what it may be?