I've recently come over to the S3 after several years with iPhones. My experience with Pandora on the iPhone was that I could pause a song, return days later, hit Play, and the song would resume.
This has not been my experience with the S3. Typically, what happens is, I'll pause a song, and sometime later, usually the next morning, I'll see that the App says Loading. When I press the icon, I get the Pandora splash screen, and it restarts. Sometimes this will happen once or twice in a day, sometimes it'll go 2 days before it happens.
Things I've tried-
-Had the phone replaced by Verizon. Replacement does the same thing.
-Uninstalled the App. Power down, remove battery for 5 minutes, power back up into Recovery mode, delete Cache partition, reboot, re-install app. I've done this, and portions of this, many times.
-I've force stopped the app. I've cleared it's data and cache.
-I've turned all battery saving off. I've tried the higher audio quality setting. I'm not running a Task manager, and I don't have an sd card installed.
-I've traded many emails with the Pandora folks. They have no more ideas to try.
Since two new phones behave identically, I'm coming to the conclusion that this is just the way it is with the S3 and Pandora. If I Google this specific issue, I don't see it being an issue though. I'm out of ideas.