From what I can gather this is one of the more common and more frustrating questions p[published writers get from readers. No, I am mostly unpublished so few people ask or I suspect care about the answer to this question as far as it pertains to myself.
I can give a partial answer though. I get my ideas from the treadmill.
It seems that more often than not when I walk power-walking (with bad arthritic knees one does NOT jog) on the treadmill as part of my cardio exercise I have an epiphany . So I have to say that teh treadmill is one place where I get my ideas.
(Today it wad food-chits and prostitution, a real break-through for my novel._