{WR} Stymied For Writing Ideas? How Do You Find Your Muse? {A to Z Blogging Challenge}

If you have written, or are writing, books or stories how did those ideas come to you? I have a few full stories written and saved on my computer. I have let them sit for months, almost a year at one point, because I had hit a wall. I didn't know where to go...until a song came on the radio (Imagine Dragons "Demons") and the flood gates opened...see #3 below!

--One came when I couldn't find anyone to go to a football game with me and my mother said I should sell my one ticket on EBAY and see who buys it.

--Another one came when a friend said my "Draco" in my Harry Potter fanfic was so far removed from canon, I needed to write an original fiction...thus "Lane Changes" was born.

--A third when a friend had a dream and I thought it'd make a great story, but I couldn't figure out the personality of the main character, until I heard a song. Now,  my friend and I are working on it together.

--A fourth just brewed in my head for NaNoWriMo a few years ago and I just wrote it out/brainstormed and came out with a 30K story that still isn't finished.

How do you find your muse if you lost it/or how do your story lines come to you?