EDIT: in case this is an iPod Touch 4th Generation:
Try this simple thing first: hard reboot your iPod (press & hold Home Button + Power Button together for ~12 seconds. If the iPod has not restarted by then, press once on the Power Button to restart it).
Let us know if it helps. Otherwise, it could be a software error that requires you to wipe and restore your iPod.
Or it may be a hardware problem that is causing this issue.
Try this simple thing first: hard reboot your iPod (press & hold Home Button + Power Button together for ~12 seconds. If the iPod has not restarted by then, press once on the Power Button to restart it).
Let us know if it helps. Otherwise, it could be a software error that requires you to wipe and restore your iPod.
Or it may be a hardware problem that is causing this issue.