my ibonez accoustic has played fine for a while. lately however ive been having a problem with some of the higer piched notes between the 10th and 14th fret. particularly the higer piched strings. some of the frets on the same string play exactly the same note. and some are just making a kind of hollow dull sound. i think that one of the fretts has popped up a little but its not visibly evident which one it is. is there an easy way to tell which one is messed up and whats the best way to fix it. i appreciate any help
Where do you live and is it winter there? More importantly, do you use a guitar humidifier? This sounds like the neck of the guitar acting weird because of it being very dry. Could be all sorts of other things, though.
Best bet is to take it to a guitar tech at a guitar shop you trust and have he or she give it a look over as soon as possible.
Hope this helps.