Checking cylinders with screw driver for knocking/pining.

I appologize for this dumb question, but as you know or will find out I am new to engine work. I used a screw driver to listen to a few of the cylinders on my stang and when I stick the screw driver directly on the block above the cylinder next to the injector don't hear anything that concerns me. When I put the screwdriver near or on the injector inlet I hear clicking. At first I was alarmed, but then thought for a second and figured maybe the clicking was the injector opening and closing to allow fuel in to the chamber. Right, wrong????? Edumacate me!!!

Thanks again.

This will probably be impossible to explain but what noises should I watch out for on the valve cover? Also, if my engine was pining would I definetly know it?

Thanks for the response.

fost9508