Jack it up if the wheel is tight to turn by hand ur caliper is binding whant u need to do is remove brake pads and handbrake cable from the caliper and then grease the nechanism using a pair of molegrips / pliars if you dont have grips were the hand brake cable sits in the caliper lock the pliars in and move the pliars up and down to operate the hand brake mechanism on the caliper it should free it up.
Also after u taken the cable off it mite be easier to bolt the caliper back to the carrier so it dont everywere when ur operating the mechanism