Welcome to JA!
Yes does sound like the park brake cables are stuck,
If you trace the cables up from the left and right sides of the reared you will see where the 2 cables connect to the 1 cable,
here is a common spot where to try and back the cables off at,
I would recommend replacing the 3 brake cables, for safety reasons and for rear brake ajustmint reasons
you will have to remove the brake drums to dis connect the cables from the shoes.
Let me know if i can help more!