Can't hear music or adjust volume on iPhone 4S?

I can hear it ring and I can hear the person on the other line. Today my son had my phone listening to music and all of a sudden the sound stopped and i couldn't turn it up. And whenever i try to turn the ringer up the little bell shows up but not the sound bar underneath. I've turned it off and reset it. What do I do?

You should check your settings and look for sounds in the general menu.