As to your question about determining the source of the problem (read: assigning throughlines to the appropriate domains), I invite you to look over Mike’s excellent post here:
As novelists, we’re often inclined to try and assign our domains not by what is actually causing the problem, but by what preceding attitude/situation/activity lead to the problem. For example, a main character is driven to act terribly towards his sister by an irrational hatred towards her, fueling a rift within the family. How would you assign his throughline. If you guessed fixed attitude/mind, you’re going one step too far! what is actually causing problems within the story has to do with his behavior. If he stopped acting that way (regardless of whether his feelings changed), the problem would go away, at least as far as the storyform is concerned.