My pause /play button not working

In that case, disassemble it with the help of the guide available here iPod Nano 5th Generation Teardown Clean the logic board and all connectors and cables with isopropyl alcohol and let it dry out after you clean it. Check for obvious damage, i.e. bad solder points etc, replace the battery and re-assemble. If everything else seems to work except your play/pause button you might want to consider a new click wheel as well. Good Luck and let us know how it is going.

iPod nano (5th Gen) Battery

http://www.sourcingmap.com/replacement-k... and other places you can google depending on your location.