I have had 2 experiences where I have edited only the audio track of a video, export it to share and it plays with the left-hand side of the screen cropped out of the view. It is almost as though Premiere Pro automatically zoomed in on the screen a bit on the left-hand side, resulting in the cropped view. The video did not need to be cropped or zoomed in, so that is not an edit I made to the original video. Both of these videos were long (20 minutes plus), so I am not sure if that is a contributing factor to this issue. However, having spent hours on the audio edits, I am hesitatant to go through that again from the original video until I learn what caused the cropped view in the exported version. Has anyone else experienced this issue?
As Ann said, it's helpful if you can post info about your sequence and clips and output settings. More or less though, just go look at your clip size (frame size), then go look at your sequence size (in sequence settings) and then check your output settings and make sure they all match the clip. That's it.