iphone 5c music disappeared

All of the music on my iPhone 5c (iOS 7.0.4) has disappeared. When I tap on the music app, it says "No Content." However, when I connect it to my computer, the computer iTunes says that my iPhone has all of its music. I tried restarting the iPhone by holding the home button and the lock button, which didn't work. Then I tried restoring my iPhone, which also didn't work. Then I tried dragging a new song from my computer to my iPhone, but the song wouldn't download onto the phone. I have no idea what caused this. One minute there was music, the next minute there wasn't. What should I do?