Hi, lets try this:
-Start a new project featuring one mono track;
-Configure this mono track Output to Stereo Out (Out 1-2);
-Insert, from >Utility<>Test Oscillator<;
-On the Stereo Out you should observe now the L/R output meter light up steady;
-Dial the Pan knob and observe the Stereo Out meter light up accordingly.
And if, after following this instructions your conclusions are affirmative, thenI think the source of your problem is hardware based. Check all of the connections for instance.
Have a nice day!