You just did a brake job and now that corner drags, runs hot, or pulls - a caliper sticking right after new pads. It is frustrating but usually traces to something in the install. Here are the common causes.
Piston not fully compressed
If the caliper piston was not pushed all the way back before fitting the thicker new pads, the brake sits partly applied and drags. On rear calipers with a parking brake, the piston must be wound in, not just pressed - forcing it wrong leaves it binding; see caliper compression tool and new pad won't fit.
Dry or dirty slide pins
If the slide pins were not cleaned and greased during the job, the caliper cannot float back and releases unevenly - a very common cause of post-service dragging; see greasing slide pins. Old dried grease or rust left on the pins binds the caliper.
A pinched or dislodged boot
Reassembling with a slide-pin boot or piston boot pinched or not seated can hold the caliper or trap pressure, causing a drag. Also, over-tight or unevenly torqued bracket bolts can bind things. Careful reassembly matters.
How to fix it
Re-check the job: fully retract (or wind in) the piston, clean and grease the slide pins, seat the boots properly, and torque bolts to spec. If it still drags, the caliper may have a pre-existing fault - see sticking caliper symptoms and unstick a seized caliper. Use quality pads and fresh hardware.