I think that wheel, which locked up again will be free if you try to move
the car back and forth. If possible, check the end of the handbrake cables
in the passenger compartment, under the platic cover.
Excess play between the cable end(s) and the grommets is not good,
(when the handbrake lever is in the lowermost position) meaning the cable(s)
are not able to return to the rest position probably due cable corrosion,
leaving the handbrake engaged.
The hammering generally not good for the wheel hubs, it could hurt the
wheel bearings, but sometimes unavoidable. You can hit the drum directly
with metal hammer, if nothing else helps.