What/who is responsible for your ideas?
In my case, it’s mostly music. I hear a song and then have a story in my inner eye. More like movie scenes, at first. Then, when I write, it could happen, that I listen to the same song over and over until my scene or chapter is finished.
Or, you go for a walk in the woods, the city or wherever, and then you see a perfect setting for a scene that would fit to your story ideas or already written chapters. I keep that scenery in my head while writing.
Last but not least: people. They are a huge source of inspiration! Either if it’s a famous person, a stranger you just saw on street, your friend or an invented one. It doesn’t really matter as long as you get plenty of ideas, when you think about that particular person. What will that person do in your story? What happened to them before? What will happen? I like to think about that.