Tale is a common synonym for'story'.
Narrative is a synonym for story. It refers to a sequence of events told or written.
I'd say 'imaginary' is a pretty close synonym. It implies something that is made up or not real, just like 'fictional'.
A 'narrative' could be a synonym for a short story. It's a way to describe a tale or account.
Well, the 'synonym back story' can be quite interesting. Take the words 'happy' and 'glad'. Their back stories may be related to cultural and historical usage. In different regions or time periods, one might have been more popular than the other. It could also be related to how the human perception of positive emotions has been expressed through language, which led to these two words having very similar meanings.
A synonym for 'love story' could be 'romance tale'.
A synonym for short story could be 'narrative sketch'.
Well, a synonym short story is likely a story where the writer deliberately replaces common words with their synonyms. This can make the story more interesting and challenging for the reader. It can also show off the writer's vocabulary skills. Suppose the story is about a journey. Instead of using 'walk' all the time, the writer might use'stroll', 'amble', 'hike' depending on the context and mood of the part of the story.
Once upon a time, there was a small 'tiny' creature. It lived in a 'little' hole. One day, it went on a 'journey' which was actually just a'strip' through the forest. It was looking for 'food' or'sustenance'.