Yes, it could be a sticky caliper, but if this is the case, you will have significantly more pad wear on that side, more than likely evidenced by much brake pedal dust. A brake line that is collapsing can also keep your brakes on somewhat, so don't just assume caliper. I've had people come in after having brakes done somewhere else, and the brake line is wrapped up in the suspension. It is also possible that the hub bearing is compromised internally, and if the grease in this bearing has become thin, it will also heat up...but this should be accompanied by a whining, and/or droning/grinding noise. If the caliper is sticky, you can exercise the caliper, apply brake grease and move the piston in and out.

Chris