What Causes Guitar Neck Pickup to Be Noisy When Using Distortion?

by mike
(MD)

For some reason there is an intense high pitched buzzing on my guitar when i have it switched to the neck pick up, but only when i have distortion on. if it is a clean setting there is no background noise whatsoever.

i checked the wire and the pick up is connected fine.

can anyone tell me why i might be experiencing this noise only when i have distortion on my neck pickup?