noises, noises

[Paulpt]

I have a couple of "noises" questions to see if anyone has had the same and was able to solve it.

1- My rear left brake (only) makes an annoying squealing sound when I step on the brake. Just in the first part when the brake is applied. The pads and rotors are fine and have plenty of life left. Anything I can put to stop it? Would anti-squealing grease will work?

2- Not super important but can't figure out why this happens. If I am listening to AM radio, when I hit the brake pedal I hear a whistling sound interfering on the radio. Any clue why this happens?

Thanks

P