Keyboard Sensitivity

I have a Mac Pro purchased this January. When I am on the net I often have to click the track several times to go back or forward on the web sites. Other times I will be typing in the address bar, a web site loads from nowhere. At first I thought I was touching the easy bar, but at time my fingers are nowhere near the bar. Usually the palm of my hands are resting on each side from the track.

Other times when I press on the track small windows appear asking if I want o open in a new tab.

Also when I press the track pad I hear a click sound, like pressing on a can.

This did not happen with my Mac Air.

I made an appointment with Apple and they felt nothing was wrong.

Is there anyone experiencing this issue.