I have 2 switches in my kitchen working as a 3 way. Although forsome reason it works single pole nicely. When I hook up the other switch the light buzzes and won't stop. What's the matter here. By the way there r3 different wires. A red, white, and green.

Green should not be connected to switching terminals, a 3 way has 3 terminals for light and control. If a green is connected to the switch, it connects to the terminal on metal part of switch.
3 ways have a pair of wires that connect between the 2 3 way switches and are called travellers, they also connect to the dark screws.
The common of 1 of 3 way need to be a constant hot, and the other 3 way common needs a wire from common terminal to the wire to the lights.
Is this in conduit?

You have to have 3-wire cable between 3-way switches.

I have no clue what this means "although forsome reason it works single pole nicely. " please tell us what you mean in other words. The wires you describe are not part of a 3way switch system, you are one short, go look again, maybe at the other switch too.

"for some reason it works single pole nicely" ?