After I lock my door, it only can be unlocked from the inside.
If your door lock mechanisms are not functioning properly it is possible that the linkage or clips inside the door may be damaged. If it is a power door lock, that uses a an electric actuator to unlock the door, that may also be a potential source of the problem. Disassembly and careful inspection of the door lock mechanism inside the door would be required to determine the proper course of repair. I would recommend having the vehicle looked at by a knowledgable technician, such as one from YourMechanic, to determine the exact nature of the problem.
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