I have an Ibanez guitar with a tremolo. When I tune the guitar, it sounds perfectly in tune when on the lower frets, but when I go to the higher frets (around the 12th), it sounds out of tune. If I tune according to that, then the open strings and lower frets sound out of tune. This always happens with me when I try to play the main riff from Sweet Child O' Mine. I want to know what exactly causes the problem, and how it can be fixed, and whether I can do it myself or I need to go and show it to a repairman.
Thanks
Ameen