Severe brake / caliper issue?

[Russ72C10]

Lately under braking (esp hard braking) the truck pulls HARD to the right. I actually have to turn the wheel left just to keep it tracking straight. It scared my GF so bad she doesn't want to drive the truck anymore (darn!) At any rate, today while taking a 15 mile drive on the interstate.... I smelled something burning. Pulled into a gas station only to notice smoke rolling out from my driver side caliper! This is when it pulled to the right the worst. I could have turned the corner (to the right) by only pushing the brake & not hanging onto the steering wheel. Well, I had to get where I was going & back home again (22 miles) - It still pulled to the right under braking, but not as hard - and the caliper was no longer sizzling.

So, this gets me to thinking. First guess is a that caliper is bad. Or maybe the brake line is bad? I bled the brakes twice after relocating the line for my lift kit - fluid came out of both sides perfectly fine (and fast) so I'm not inclined to think a line is pinched. But maybe? I had an alignment done so it does drive & track straight. It only acts up under braking. But it has to be fixed... it's simply not safe.

Any advice? Opinions? Experience?