Hey, I have an Epiphone PR5E acoustic-electric guitar. Recently the "A" string started buzzing, and it's pissing me off. Anyone know how to fix it? I checked and it doesn't seem to be fret buzz, the buzz comes from the bridge/nut. When I tune the string down the buzzing stops. Right now, I've tuned the guitar down a half step and there's no buzzing. But I'd like to put it back to standard tuning without the buzz. Anyone know how to fix it? The strings I have on right now are light gauge, should I change that?

PS. Sorry if I post this in the wrong section or something, I"m kinda new here...