Lately I've been having some really messed up tuning problems. When I get it in tune and bend a note or use the trem it just goes straight out of tune. I think it is because the strings are getting caught up on the nut, because when I bend a note it pulls the string back but its not sliding back so it goes flat. I think im going to put some lubricant on it and see if it helps,but dont want to screw anything up. has this happened to anyone? any suggestions on how to fix it?