Stop. Stop. Stop.
Save your work now.
If you have not read Master Documents "Feature" yet, do so now. It will explain why few people responding on these forums have much positive experience with it. John McGhie put it succinctly when he said that "there are two kinds of Master Documents: Those that are corrupt and those that will be corrupt soon."

Once you have read that, if you wish to continue using a Master Documents structure, say so and someone will try to help you.