Dual Knobs Sticking Together

Try pushing in on the circle knob (closest to the radio). That might separate them enough. If not, place some blue tape on the front of the radio, and you can pry them loose with a tool preferably made of plastic or wood. Once they are loose, carefully push them back on, making sure they have enough space to spin freely. 

Shown below are a few examples of what "Dual Knobs" look like.