That's why the Greeks had the idea of "muses" (goddesses who gave ideas to creative artists).
It is one of the puzzles and miracles of human existence that ideas "pop into" our minds.
Science-fiction authors complain of frequently being asked "Where do you get your crazy ideas?" According to Isaac Asimov, a writer named Harlan Ellison liked to answer this question "From Schenectady. They have an idea factory and I subscribe to it, and so every month they ship me a new idea."
The great American writer, Jack London ("The Call of the Wild;" "White Fang;" "To Build a Fire;") could tell a story wonderfully, with great "strength of utterance," but had difficulty coming up with ideas. He even got into trouble over accusations of plagiarism because of it. "The Call of the Wild," for example, had too many parallels with an obscure book, "My dogs in the Northland" by Egerton Ryerson Young). Interestingly, at one point, he actually had an arrangement with a young writer who created and sold plots to Jack London. The writer, Sinclair Lewis, later became famous in his own right ("Babbitt," "Main Street," and lately I've been re-reading "It Can't Happen Here.")
Clearly, we have a lot of mental activity we are not conscious of. I think part of the process of growing up is for the conscious part of our mind to give up the idea of being in control, and to get on friendly and trusting terms with the part of our mind that the ideas come from.
The writer C. S. Forester, who wrote a really wonderful and entertaining series of novels about a fictional naval captain named Horatio Hornblower, said that to him, writing was like using rope to lower a plank of wood into the ocean, and hauling it up from time to time to see what wonderful mosses and barnacles and seaweed had grown on it.
In English, we spell "Evrica" as "Eureka!" (Usually with an exclamation point after it.)