If you enjoy writing, this will happen no matter how good a storyteller you are. This will occur with some frequency, especially with the longer stories you write. Even with the tools of character bios, index cards, and a good story outline you will write yourself into a box.
I have plot hole or two that needs little filling, and I need to develop one character into someone far more compelling or my audience won't care what happens to her. It is a dilemma, but these are boxes to which I thoroughly enjoy writing myself out. I strongly believe you must love the process in order to keep going. You just can't say you want to be a screenwriter; you have to write screenplays that other people want to turn into a movie.
It seems everybody at one point in life imagines they could write a screenplay. I think all it takes is one really lousy movie, and viewer leaves the multi-plex thinking, "I could write a better script than that!" and another screenwriter is born.
But in reality, let's say you have one hundred of those would-be screenwriters. Out of those, eighty haven't clue what they are saying, and their best idea is still not written at all, but just a germ of an idea. Twenty have written something, but twelve of that twenty are using the wrong formatting or style and not to the discipline, for they don't know how. The eight remaining may know something of screenwriting, but, out of that group, five of them use a Word.doc and don't have a translatable software to a production company. So, I always figure, I am not competing with thousands for getting a spec recommended, but maybe just a few other people that day.
It's just another box, another obstacle I work through or around.