Help: Is it the shocks?

There is a sound coming from the rear on the driver's side when I start to accelerate or when going around a bend. It seems like some loose object rolling around in the trunk. I checked my trunk and everything is locked down. I thought my shocks were gone and so I checked into a garage. However the mechanic said both my shocks are still fine. He added what he called "spacers" on the mounts of both shocks and said all would be fine. His reason was that the sound was caused by the springs around the shocks. I now do not know what is causing this. A search of the forum has not helped.