Perhaps the problem is not so much that what you want the story to be about is hard, as it is a research problem.

Maybe the thing you want to be the story about is outside your area of expertise. It's possible you need more imput. More info. An expert opinion.

Science fiction is like that. It forces you to go a little beyond what you know and use what you learn to build a bridge so *other* people can get there.

Good luck to you.

- Meg