Seems emergency brake is not releasing

When I release it then start in reverse often the car doesn't move then there is a loud sound from the right rear tire. If I don't engage the brake it reverse fine.I don't know where to start with this. I assume there is a cable going back to the wheel cylinders. Perhaps binding up somehow.

Jack the rear of the car up.....apply ebrake......try to manually move the rear wheels......

Now release the ebrake...do one or both wheels move? If one moves and the other doesn't, then you have a problem on that side....

Discs or drums on the rear?

With someone applying and releasing the ebrake, can you see the cable to the bad wheel moving?