Rattling noise, rumbling noise at the rear of car

Hi There,
i hope you can help me. I drive 1997 cavalier Z24 2.4 engine and i'm hearing a rumbling, rattling noise whenever I drive only at the rear. I've brought it to the shop and the guys cannot figure it out. I've heard strut bearings, struts, but nothing is comfirmed and i'm tired of paying money for no results but just for looking at it. I've had the car now 3 yrs and the noise was always there but now it's getting annoying(when the music is off I hear everything) pls help me. Anything would be great from you guys. Thanks in advance. Look forward from hearing from you. Take care