Hi again Jenny!
The reason you ask what direction the stress line is coming from is so that you cure it at the source. If the line was coming in from the front direction, you would cure it in front, where it enters your property. It would then have no impact on the back, because it has been cured at the "source."
If the line is coming in from the back, you would cure it in the back, where it originates. It would then also be cured in the front, because it would be neutralized at the place where it impacts your property.