that sir is a £64000 question, who knows ?? it may be fine or it may lock again. it may also be another fault, dont know untill the wheel & drum comes off.
how long was the car sitting there with the handbrake on? few days or a few weeks?? it may be caused by the handbrake cable, you took off the hand brake but that one wheel remained on full brake
untill it has been checked out , no one really knows the answer.