The Yellow Bird Sings by Jennifer Rosner

In a barn, in Poland, a young girl and her mother hide from the Germans who seem to be everywhere. Days and nights spent mostly silent do nothing to stop the music that seems to live in the girl's soul.
Later, in a decision no mother should ever have to make, Shira goes on to be hidden in a convent and her mother goes on the run alone. Shira, a music prodigy, goes on to a musical career while her mother never gives up her search. A poignant look at the horrors of war and the incredible amount of faith and inner courage that it took to survive. Fans of WWII historical fiction based in truth will be moved by this story.