I have pulled the car backwards out of the garage for about 10 feet
Herein lies the problem i suspect. Due to the way the shoes work with a leading/trailing edge, i fancy as you have pulled it out, you have drageed a swollen shoe onto the drum.
Saying that, after 8 years, it could just have bonded the drum to the hub face. Does the wheel spin? If not, heat the drum to dry the shoe, let it cool then clump it with a copper hammer.
If the wheel does spin, wd40 between the hub/drum and let it soak.....then copper hammer.
Last time i had one of them, i banger raced it.