@Ninemmruger When listening to a station, you can "replay" the song that is currently playing to start it back from the beginning.
However, you wouldn't be able to press a "back" button to replay previously listened to songs on that station.
This being said, with Pandora Premium, you would be able to scroll back through your Recently Played list, and manually press play on a song you heard previously.
For more information on Pandora Premium, or if you are interested in upgrading, check out this page.
Hope this helps!
