Trackpad messing up

I've had my MBP since November 2009 and recently my trackpad has decided to malfunction. It clicks, highlights, and does whatever it pleases on its own. It works sometimes after a reboot. I know it's not any lotion on my hands or anything like that (that was a problem before). I went to the Apple store and they told me I needed a new trackpad but they didn't do any diagnostics on it.

Has this happened to anyone else? Do I really need to get a new trackpad?