Using Windows 10. I only appear to be recording one channel. I am recording from vinyl LPs via a USB socket in my PC. The Audacity trace shows both channels but they are identical so effectively I am only getting one channel.
In the past (probably an earlier version of Audacity)I have used the same method of recording Vinyl and transferring to ITunes with no problems at all.
Right click on the Windows Volume/Speaker icon, go through the menus to find the USB device and make sure Windows is configured for 2-channel stereo.
Are you sure the record is stereo?
Do you have a USB turntable, or are you using a USB interface?