Julia Cameron, writing guru and author of The Artist's Way, suggests that you can transform a hang-up into art. Her advice is to think of five secrets or events from the past that still bother you and write about one of them.
It's a great starting point for a story, novel, or screenplay because there will be emotion behind it. The mistake that many writers make is thinking they have to tell the literal story of what happened to them--being bullied, or a shoplifting incident, or telling a secret a friend asked you to keep. Often it's much more effective to transfer the basic situation to another context, or to use it as a metaphor.
For example, the bullying incident could become a sci fi story about an entire race that is subjugated.
Telling a secret could become a more fanciful children's book in which a farmer tells his dog a secret, and the dog tells another animal, and the secret gets stranger and more alarming each time it's told until it makes its way back to the farmer as a totally different story.
If you're casting about for a new story to tell, or to inject new life into one that's gone a bit flat, looking how something bothersome from the past that might be integrated, literally or metaphorically, could give it the energy it needs.
(There are loads of tips on how to write in my book, "Your Writing Coach," published by Nichoals Brealey and available from Amazon and other online and offline retailers now.)