Nikkor 18 - 55mm f/3.5 - 5.6G lens problem?

It won't auto focus.i've set it to A but nothing happens. I hear a clicking sound, but no auto focus.there's no problem if i adjust them manually.need help. Is it broken? Or just something that i must tweak at the settings?

Added (1). Oh.i've never dropped the camera. Just saying.

Is the switch that toggles between auto and manual focus on the camera body set to auto, too?