Dropped Nikon D7100: clicking sound and viewfinder image jumps — should it be checked?

Yes—it's worth having the camera checked, especially after a drop. Cameras contain many precise, low-tolerance parts, and impact damage can worsen over time even if the camera still seems to shoot normally.

Before assuming the body is damaged, isolate whether the issue is coming from the lens. If your lens has VR (Vibration Reduction), switch VR off and see whether the clicking and viewfinder movement stop. Also try a different lens if you can. A faulty or active VR unit can cause movement and sounds that may seem alarming.

It also matters when the symptom happens: during a half-press, while metering/focusing, or only when taking the photo. That can help identify whether the source is the lens stabilization system or something mechanical in the camera.

If the behavior is new after the drop, the safest advice is to have it inspected sooner rather than later.