98 e150 right rear brake not releasing

it only does it intermitently. lately getting worse. pretty sure the drums could used turned other than that they look fine. sometimes when going slow i can feel it grab, release, grab release. wheel cylinder maybe??? today it would not release and left a big scrap mark it my stone driveway because the tire would not turn for about 5 ft

I would put in new wheel cylinders and new brake hardware, springs and such. The original springs lose their tension from heating up and cooling down hundreds of times. The drums have to be replaced if they are worn over 1/8 of an inch. When you get the shoes to do the rear brakes place one of them inside the old drum. If it doesn't make 100% contact replace the drums. Take one to the boneyard and get some replacements.