Loud whistling sound in kitchen sink

[kminter]

When I turn on my faucet there is a very annoying, high pitched whistling sound. It started out only from the hot water faucet but has advanced to both the cold and the hot water faucets, with the hot water still being louder. HOwever, if I use the sink sprayer there is no whistling at all. HELP!!

[HayZee518]

clean out the strainer in the faucet. unscrew it from the spout and clean it out. there's a nylon insert wiith tiny holes in it.