Please bare with me while I describe my issue. When I get home from work (about 4pm) my GS3 is usually playing music from the Play Music (Google Music) through the headphone jack to the speakers in my car, the music is paused and that's that. Next morning when I connect my bluetooth headphones with my phone, whichever song was playing the day before starts playing, but when I go to the 'Play Music' app there's no indication of the song playing, and if I click on a song to start playing then both songs play simultaneously through the headphones. Force Closing the app or restarting the phone takes care of the issue, but this routine never caused issues until I upgraded to Jelly Bean. Is anybody else having this issue?
I've been having problems with Google Play Music since the upgrade as well. I will play a couple of songs in a row and then will stop but when you look at it, it appears as if it is still playing. Seems to be just freezing. I have seen several people on this forum complaining about the issue since the JB upgrade.
I've had that happen also, and sometimes with an auxiliary cable plugged in the audio stops going through the cable, and it starts playing through the phone's loudspeaker. I also just noticed for my original problem force stopping the application doesn't actually stop the song from playing.
I know the frustration of not having the ability to play your music properly. I would love to help. For Music Player application, it has option under application settings for Music Auto Off for different values, please select to Off. It may be the connection to the car. Let me know if this helps. Have you performed a hard reset. Sometimes after a major software update, the phone works better after a factory reset http://support.verizonwireless.com/clc/devices/knowledge_base.html?id=59267 . Keep us posted.