macbook air frozen screen black bar on right hand side

Hi

I have a macbook air (2013 model) and recently when I have been using it, suddenly for no apparent reason the screen will shift to the left, so that the apple logo on the top right corner nearly disappears completely, and a black bar appears on the right hand side of the screen. Nothing responds unless I hold the power button and then press enter to shut it down. This has happened to me twice in the space of a week. Can anyone help me with this problem? Is it common?