Whistling pipes HELP

[topman]

Over the past few weeks this problem has worsened

When turning off any hot or cold taps in the house there is loud whistling noise which takes ages to subside

I have tried shutting off the mains and running the cold and hot taps to dry and then refliing the system and have altered the mains water pressure but to no effect

Can anyone help or is this a plumbers job?