What causes brake pads to be permanently pressed against rotor?

[ayeyew]

My right front brake started making grinding noises yesterday, I noticed that even when i was not braking (particularly at low speed) the grinding noise was still evident, making it seem like the pads were still pressed against the rotor, even when my foot was not on the brake pedal. I bought new pads today, put the girl up and rotated the right front wheel and the grinding noise was evident.

Changed the pads, the inside pad on the right front was bare, but the outside pad on the right front was still very meaty. The inside of the right rotor was severly scratched, i am going to replace them next time i need pads.

The pads on the left were still meaty also, but i replaced them anyway.

After i replaced the pads and put the wheel back on, it was near impossible to make the wheel rotate. I took it for a quick drive (2-3 mins), came back, jacked her up and, yep still damn near impossible to make ther wheel rotate.
I put my hand on the middle of the right rotor and it was hot, the left rotor was not hot at all, so i kind of figure that the pad is pretty much permanently pressed against the rotor.

I lubed up the 2 bolts holding the caliper in, but what could be causing the inside brake pad to be permanently pressed against the rotor

What do i need to do to fix it?

Cheers