91 cavalier many questions

i have new brakes pads rotors shoes combi kit flex lines and they were done 2 weeks ago now im getting a constant chirping and when i press the break it makes a grinding and skreeching sound i cand see anything wrong whith the wheels off. the vents are not blowing either the heater motor works fine but no air or ac through the vents

The grinding I don't know about, but the screeching could be vibration. There's rubber built into the calipers that can dry rot and break off easily while changing. It's easily replaced once you get the calipers off.

Of course, it could be something else.

I have a 91 also and I just had the screeching/squealing a few months ago after replacing by brake pads, rotors, and hoses. replacing the rubber fixed it.