Quick & simple... jack up the rear and spin wheel to see or hear if dragging.
For the most part it should be able to spin without grabbing.
If you have drums, it's a good chance it's the portion valve that pushes out both ways to activae the drums. I had that issue with my g/f's truck last winter. Usually just a $15 dollar part, but if you replacing it, replace both sides... not just the one side.
If you have Calipers, another easy way besides spinning the tire is try pushing the Caliper Piston back in with a c-clamp and if it's very tough or is binding, then time for new Calipers.... both of mine locked up on my this past summer while at the Mall. Made for a fun street fix in the parking lot and everyone asking if I was alright or needed tow truck called.... I was like nope have it under control, walked across street to AZ, bought the calipers & fluid and replaced in parking lot.