My car was in an accident last month (front passenger side & quarter panel collison). Got the car back last week and
it runs fine but noticed there is a metallic squealing sound like a wheel is loose or rubbing against something. It's noticeable
only when the air conditioner is turned on and the car is driven more than 20-30 mph. That and I would swear that turning
on the air seems to cause the engine to make more noise now when turned on too than before.

Any help is appreciated. Thanks.

Take it back to the body shop and have them help you troubleshoot. It may have been damaged in the accident or subsequent repair work.