Your car won't start unless you pushed the shift lever forward in park. After a while it would not start in Park so you put it in Neutral to start and that worked. Now it won't start at al?
The Park and/or Neutral switch is out of adjustment. There is a hidden switch that must be engaged by mechanical means in order for the starter motor to be engaged. This is to prevent accidental starting while the car is in a forward or reverse motion gear, which could result in the vehicle moving in an undesirable direction.