My iPhone 6 started playing music when I plugged in my ear buds.
I did not have any apps open. It was playing something thing that sounded like a radio station, and it was nothing that I have saved in my I tunes Library or any of the Pandora stations I have saved. I don't follow any pods casts or have any e-books on my phone either. Where did the music come from?
iPhone 6, iOS 8.3