Sound can only come out of one side in Waveform workspace

I mix a film in Audition.  The sound has been recorded in multi-channel wave files.  In the MULTITRACK workspace, all the different channels are on their own separate tracks.  If I solo one track, the sounds comes out of left and right, in mono, no problem.  But when I double-click on a clip and get into the WAVEFORM workspace, one of the channel is in color and the ones are greyed out.  When I play the file, the sound can only come out in either the left or the right side of the headphones, depending on how I mapped it in the Preferences.  There is no way I can monitor the sound on the left and right at the same time.  I spent 3 hours with an Adobe representative and no matter how I explained the problem, he didn't understand the issue.  I done a ton of research online and nobody posted anything on the subject.  It's a very simple problem, I can't believe I'm the only one who experienced it.  If anyone had the same issue and resolved it, please help me.  Thanks.