Hello!   I'm having some troubles on my guitar, I started having some weird fret buzz only on the D string, and only on the 5th fret but the buzz is coming from the nut. If I fret the 5th and gently press the string behind the nut, the buzz almost goes off (sometimes it goes off for like 15 minutes when I release it). I did check for maybe a widening of the nut (plastic) and it seems like a little wider than the string but it doesn't buzz when played open. Any suggestions?   Thanks!   EDIT: D st