simple check for caliper sticking - jack up car, rotate wheel by hand, does it spin freely? then OK! apply brake and try again - if it doesn't spin free, tap the piston sode of the caliper with a soft hammer (rubber, plastic, even a piece of wood), if it spins free now, your caliper is sticking.
These days most calipers just get replaced with rebuilt ones, but they are really easy to clean if you want to save bucks - the problem is usually from corrosion buildup behind th sealing ring causing it to press on the piston constantly preventing normal retraction.
disassembly and cleaning is all that's normally needed (paying special attention to scraping out all the crud in the sealing ring groove) you don't even have to replace the rubber parts unless damaged. this is more common on aluminum calipers such as on motorcycles but it happens to all of them eventually.