It is not clear exactly the issue is from your brief description but it sounds like your battery is dead. Unfortunately, iPod batteries are not removable/replaceable, you would have to have Apple fix this.
An alternative is that you might just need to reboot the thing. I'm not sure how to do this on a regular iPod but if it is a touch, you would hold in both the power button on the top as well and the main button on the front. After holding both of these for around 5 seconds it should force it to power down allowing a cold reboot.