My device!!

iPod service and repair: https://support.apple.com/ipod/repair/service

Seems exactly what the guy before said, your entire lock switch assembly is broken. I suggest using AssistiveTouch (Settings>Accessibility>Accessibility Shortcut>AssistiveTouch, press home button 3 times) as a temporary lock switch

I wasn't referring to the scratches. If your iPod hit the ground hard enough to dislodge the button, it's fairly likely that the fall has broken something inside. The break may be that the switch has broken off from the circuit board, which may mean that the switch no longer works, or it may be something more crucial, that causes the iPod to intermittently fail to do what you want.

It will be your decision, but if the iPod appears to be working, and only the lock button is not, you may be better off just putting up with the damage. Unless you know what you're doing, you may cause more damage by trying to get into the iPod to repair the button.

It sounds as though the damage is significant, so even if you manage to get the lock button to go back into position (as your uncle has tried to do), the chances are that the connection between the lock switch and the rest of the device may have been broken. Does the iPod appear to be working correctly?

Even if that connection is okay, it seems likely that there could be considerable damage to other parts inside, any one of which might cause the iPod to stop working correctly.

I think you may have to accept that the iPod is beyond economic repair. In other words, it will cost so much to repair that you might as well buy a new one.