Hello mate!
There should be a menu for your sound levels. Some phones don't vibrate when plugged into charger... some other phones dont turn off their display when charging...
Do you have any apps that allow you to change rings tones of your phone? Try to reinstall them and put another ringtone. Is your ringtone a mp3 ? Try to store your ringtone file into your LG memory (dont put ringtones into your SD card). Is the problem still remains?