How can I prevent my music from stopping on iPhone?

I start listening to music that suits my mood, give my attention to other stuff on my iPhone. After a while my system shuts down and I have to restart the music. Sometimes over and over and over...! I want to start the stream, lock the system so it will keep playing with no further intervention by me, all day if necessary. How do I do this?

[Re-Titled by Moderator]