Had one about 1981 where a person (not me) in a Bronco froze the shoes to the drum by leaving the ebrake on too long....he put it in low, reved the engine and popped the clutch. It was kinda cool....first time that I ever saw the shoes rotate with the drum. Kinda messy though since the wheel cylinder broke off and tore the brake line.

Try backing off on the adjuster and then rocking the vehicle....dont use too much force....push/pull by hand.