One of the ways of making an existing stereo signal appear wider and even appear to be coming from outside the stereo speakers is to take a little of the left channel, reverse the phase and mix it into the right channel and vice versa. To do this in Pro Tools you can do it two ways. Either way duplicate your track so you have two identical tracks, now either insert a Trim plug-in on the duplicate track and press the phase reverse button
or use the AudioSuite Invert plug-in that you will find in the Other group and create an identical set of regions that are phase revered. Either way flip the pan controls of the duplicate track so left goes to right and right goes to left.
Finally introduce a small amount of the inverted track and listen as the track gets wider. Push it too far and you will get a hole in the middle and it will also play havoc with the mono compatibility.