Macbook Air trackpad clicks twice

I am using a Macbook Air (about 2 years old) running OS X Yosemite.

The problem I am having is that sometimes when I double click a file, two are opened.

I initially blamed this problem on Chrome as html files would always open twice, and I couldn't right click some extensions. However I have since found out that these issues do not occur when using an external mouse. This is leading me to believe it is an issue with the trackpad.

Its not the end of the world, but if there is a solution I would like to know it.

Thanks

J