The Library of Congress subject heading for shyness is actually Bashfulness. Books about Bashfulness have the call number BF575.B3. Books on the subject of Bashfulness in adolescence have the call number BF724.3.B36. The call number for Bashfulness in children is BF723.B3. A broader term is Emotions or Fear. A related term is Timidity.
These articles were selected by searching article databases using the terms "shyness AND teens" and "shyness AND children."