98 Jimmy rear brakes sticking

I just did a brake job on my girlfriends Jimmy.
It has 4-wheel disc brakes.
Now the rear brakes seem to be sticking.
I did not turn the rotors.
I noticed that the calipers seem to have adjusting/lock nuts on outer caliper bolts; could I have tightened these too tight?

thanks,
from a newbie to the forum...