iPhone 4s camera weird noise

When I put my iPhone 4s down on any even slightly hard surface, the portion near the camera makes a sound like there are loose parts inside. Is it normal or do I need to get it checked? The sound is not from the speaker. When I tap the area over the griffin case or the naked iPhone body it makes the same noise. An worried bout the camera sha I get t checked or is it normal as the camera has real tough optics n lots f lenses