What is this fluttering in my ear?

I have a little winter cold at the moment. You know; a runny nose, stiff joints, a little cough. Nothing that bothers me much, but there is this fluttering in my ear that is really annoying. Every little sound causes my eardrums to flutter, to rumble. As if every sound triggers an overreaction in the little bones in my inner ear. It sounds like someone tapping with his fingers on the skull around the ear.

Does anyone know what causes this (apart from that cold I have), what actually happens and what I can do about it?