Either caliber is bad. or break line is clogged.
Bad caliber or brake line
Warped rotor(s).
Warped brake rotor.Warped brake rotor.
Possibly warped brake rotor/worn brake pads. Get this checked out.
Corroded brake wheel cylinder, or caliber, parking brake stuck.
There could be several reasons such as, you forgot to release the e-brake and drove the vehicle with the e-brake on, or a grease seal went bad and grease is getting onto the hot brake drum or brake rotor, or brake fluid from a leaky wheel cylinder or caliper is getting onto the hot brake drum or brake rotor.
A brake rotor heating up would probably be caused by a sticky brake caliper or a collapsed brake hose.
brake hose is bad
A vibrating brake pedal is an indication of a warped rotor. Noise is common to disk brakes but depending on the noise it can mean that the brake pads are worn out and you are due for a brake job.
sounds like your brake caliper is sticking. This would cause the pads to be in constant contact with the rotor.
If the brake pads are not worn out check the backing plate. It is the thin metal plate behind the brake rotor, sometimes it will get bent and rub on the brake rotor.
You may very likely have bent the thin metal backing plate behind the brake rotor. That will cause the backing plate to rub against the rotor and make an awful grinding noise. Its not too hard to reform the backing plate away from the rotor.