Turn off your CB.
If you want a better answer, give more details, like what radio you are running, has it been butchered by yet another CB hack; are you running an amp, if so, what is it; what antenna and coax are you using, what is the antenna height and orientation to your neighbor; are you running a filter, what kind; is his TV on or off when you come through the speakers.
"You got questions, we've got blank stares!"