Noise from right rear side

I have a 1997 CRV with only 54,000 KM. This started about a months ago. The noise only come out during driving. It sounds like a rock rolling inside a plaster box or a very tight spring. I thought that it was the exhaust system. But I checked under the car and shake the exhaust pipe and muffler and found nothing loose. I also tried to jump up and down inside the car when it is stopped and found no noise. Can that be the suspension ? Any suggestion ?