Panning doesn't work on speakers

Are you using the onboard soundcard of the computer? Or a different audio interface? What's the model name of the speakers? To which output are the speakers connected to, exactly (how is the output labeled)? What are your current output (range) settings under Preferences > Audio > Device?

Thanks for the replies- Yes, the master is definitely not set to mono, and like I said it works in headphones but not in speakers.. Solger- let me see.. so the speakers I'm using are pretty basic Logitech speakers, Logitech Z313 to be exact. I'm not quite sure what you mean by the soundcard of the computer or a different audio interface? I just plug in the speaker jack into my computer and run it into the computer speakers.. I'm using a Dell PC and on the side of the computer it has one output with the headphone symbol and one for speakers.. In Reaper, under my 'Device', 'Output' setting, I have the option selected for 'DX speakers' or something like that- one of the few options the built-in settings offered.. Let me know if that makes sense. Thanks again!

Don't know the Dell PC but usually I'd expect to find some kind of software that gives you at least limited control over your on board speakers, possibly in your Control Panel. I'd have a look there and see if there is an option selected to link them (or some such).