#1
If you have a high quality guitar,
not a fret buzz where it's like if you're just playing that single note it buzzes,
but like if you're playing a chord, or if you do an action of some sort and you hear a buzz.. like say a double bar chord or something.. I donno.. Is it because you just suck at the technique?
#2
mmmh what guitar is it?

it could be your technique, or you should get more power in your hand to get those chords...
but I don't really understand what kind of buzz you're talking about
#3
By buzz, do you mean buzzing from your strings, or from the pickups? If it's on the strings, go down a gauge in strings and PRACTICE! If it's the pickups/electricals, you might have an earthing problem or some loose connections. If it's just something loose, you can probably resolder it yourself if you are handy with a soldering iron. If it's bad earthing, you might need to take it back to where you bought it from, and see if they will correctly earth it for you.