PP has a history of issues with USB audio devices. My recommendation is to not use one. Connect a mic to the Mic input of the motherboard/sound card.
I had the same problem with my USB mic on my MacBook Pro. I created a new aggregate device to fix it. Here is a link for Premiere Pro CS6 and Mac OS X, but you can adapt the instructions for Premiere Pro CC.
Not sure what to suggest for Windows users. Let us know if you have any questions.