Panning not working - only mono tracks

Hi all, New user here. I have the following problem: Panning is not working in Reaper at all, when I turn the knob to the left it is full volume and when to the right no volume at all. I have also noticed that all tracks are by default in mono. For example, I inserted a stereo media file and the problem persists. I have tried the same in Audacity and works absolutely fine. Mu audio interface is a Focusrite Scarlett 2i4 1st generation. Any help is appreciated Thanks

sounds like you have a stereo track ie separate left and right tracks with audio only on the left track

Issue solved. Apparently there was a VST left in the Monitoring FX section (Upper right corner next to the ASIO settings). Once removed everything is back to normal

Same problem 

I'm having the exact same problem. I'm on a Mac, using an Onyx Blackjack audio interface. In Garageband, I can set the input and output separately, so I can use the default audio output and it pans fine. But in Reaper, oddly enough, you have to chose the same source for both the inputs and outputs, so when I do that, I can't pan while recording. However, when I record something, then listen to it through the default system outputs, I can pan just fine. Any advice?? =(