Terrible brake PEDAL noise

[Bottomlesspit]

I am getting a horrible noise from the brake pedal. It is definitely coming from where the pedal rod goes into the firewall....that area with the rubber boot over it. The sound is something like walking in wet tennis shoes?! Everytime I push the brake pedal down in goes Wreeeeek. It is loud.
I sprayed different lubes all in the boot and around the area, but it had no effect.
I can sit idling at a stoplight and push the brake pedal down over and over and the sound is very loud and never stops (of course I don't sit there and play with the pedal like that all the time).
I had the brakes all worked on last month. The sound was there before and there is no change since.
I can't tell for sure, but while pushing down on the pedal, and this noise is happening..............it feels sometimes like the pedal is lightly vibrating as it goes down......maybe a light grabbing action. Again...like wet rubber rubbing together.
Anyone have ideas, experienced this, or suggestions? I have never driven a vehicle that felt like this, or made such a horrible, inside the cab, sound.
Thanks to all,
Ken