My iPod doesnt play music and shows the battery and play symbol.

Hi, I was out running today and all of a suddon my iPod stopped playing music and froze. On the screen it just shows the battery symbol and a play symbol together. If I press any buttons on the iPod it makes the sound but screen doesn't change. It won't play music either. It charges fine as well so I'm a bit stumped?!? Do have any idea what it could be?