I am facing a strange issue with my track pad. My machine is a MacBook Pro Retina Display (Mid 2012) updated with Yosemite. So when i click on the track pad's right side, the track pad clicked down properly but nothing happens, although the left side is working properly.
What if you click while holding two fingers on the track pad?
If that works then it might just be the setting: from System Preferences, Trackpad, you're looking for the setting pictured in the following screenshot.
(Screenshot courtesy of wikihow.com)