I have an Ibanez Gio ( my learning guitar until christmas ) run through a wussy blues fender princeton 65 solid state, my cable is pretty good, gold tips and what-not, and I do not believe this is a feedback problem as it occurs whenever the amp is loud enough to hear at all, and I use controlled feedback all the time and recognize the sound.
Please help, I assure you my guitar does not move when I play, and neither hand irritates that ringing string.