Answer:
you are (i hope) talking about REAR brakes, there is a little trick.
you should see a large Phillips head screw in a hole in the brake drum. remove it anscrew it in the other hole and as you screw it in it will slowly break the drum free.
there are a couple of cautions, usually the screw is in the first hole is tight because of road dirt . So use a large Phillips head screw driver. If you mess up the Phillips head screw you will have a devil of a time getting it out.I find a good rap with a hammer on the end of the screw driver will shock the screw loose. Oh the other thing is sometime the adjuster is up tight and needs to be slackened off to allow drum brakes to retract a little so you can slide drum off.