Make sure that the shoes spring back away from the drum without hanging up. Spray the moving parts and friction areas with WD-40. Perhaps even a little bit O grease. You may find that only one shoe is rubbing. This can happen if the shoes are not "locked" into place when installed but should be evident when adjusting them.
Readjust using the star wheel then get back in the truck and hit the brakes. Repeat this process a few times until the shoes are seated properly.
