how can i fix the locking system in my mk4 golf?

hi i have a 99 vw golf 1.4 and the locks have a mind of their own they lock and unlock by themselves while i drive on the road and when i close the front passenger door especially i usually have no problem unlocking the car only for the odd time it would want to lock again after opening any doors immediately after unlocking theyre drivin me mad does anyone know the problem and any quick fixes for the problem