Stereo audio changed to mono?

Hi, I am new to PP... I originally imported 4 video clips  and 1 stereo clip to sync up for a music video.  I used the 4 video clips to create a multi-cam clip successfully. The first thing that I did was to drop the audio stereo clip onto the time line and it played great and was in stereo. After I created the multi-cam video clip the stereo audio clip disappeared from the time line. Now when I drop it onto the time line it will only play as a mono left channel track. I cannot find any info as to how to get back to a stereo master track to sync up to the multi-cam video clip.  Any thoughts?  Thanks, Quasar