hello:
Simply order a new door latch assembly for the door with problem (mostly drivers side door) thru ebay, Amazon or Partsgeek and have them deliver to you ( about $55 delivered), take to an auto service shop and they will install that for $65. After that it will work great. Door problems are due to wear and tear and latch assemblies fail and need replacement. This is a maintenance problem, like changing water pump or any other part of the car. I don't think any other way of fixing will work.
Kumar