The curse of the white page or the empty screen.
Listen to these words from David Martín, the main character in Zafón's "The Angels Game":
"Inspiration comes when you stick your elbows on the table and your bottom on the chair and start sweating. Choose a theme, an idea, and squeeze your brain until it hurts."
Good luck with your inspiration. Don't just wait, but work for it!
"The Inspiration of Saint Matthew" by Caravaggio.