Once upon a time I thought I was badly uncreative, too, and then I developed my super-secret Build a World with Logic Alone method, which I'm going to share with you tonight for the low, low price of nothing at all!
"But my story is set in the real world!" I hear you say. It isn't, actually, unless you're writing non-fiction, but that's kind of a needless quibble. You'll see why later.
"But I want a story, not a world!" I hear you say. Part of the secret is that your world is your story. This is a strong statement, but as far as I can tell it's the truth. Your world determines what kinds of stories you can tell and what the details are. The shape of your stories follow the shape of your world, and by telling stories you wreak change upon your world which in turn begets new stories.
So here we are: the method itself. First, pick an event in your world. It's probably best if it either follows from your story, precedes it, or doesn't affect it too much. Ask yourself questions about that event: what happened? Who did it happen to? Why were they involved? Why did the whole thing happen to begin with? What are the consequences? What were the circumstances leading up to it?
I'll give an example. The whole of the setting of Many Words' currently running story was derived from the words, "The Threshold Rebellion". Obviously, it involves Threshold and some other party. I decided to call the other party the Confederacy. "So why were they at odds?" I asked myself. It developed that the Confederacy was a government of a handful of star systems, and Threshold was unhappy with increasing centralization. So why did it only happen now, when we have eleven star systems with colonies of approximately equal development a good long way into their lifetimes? Obviously the systems would have had to be colonized at around the same time, a long time ago, and none of them can be Earth. Why didn't the centralization bit happen earlier? Because they didn't have an FTL drive until recently.
And so on. I could repeat the process for pretty much any of the other worlds I've come up with, but it boils down to this: come up with one idea, and figure out why that idea makes sense. It does (as I said) even work for stories in just-like-today worlds. Stories shape your world after the world ends, so ask yourself what the world would look like once your story has run its course. If that doesn't make sense (murder mysteries seem like they fit here), ask yourself what happens if your protagonists fail. Pick some event from the post-story world, and the very process of making that make sense is basically the same thing as outlining your story. The only difference is you have a point of reference to work against.
There is one final point: it's difficult to do this alone. Find a friend and have them play devil's advocate. It works out a lot better in the end.
Hopefully I've been helpful here as opposed to unintelligible.