Here’s a short list of suggested reading on various topics
We are born with an innate creative capacity but often either never learn to cultivate it, or worse, through environmental influences and self judgment have managed to damage that capacity. Creativity is a universal inborn capacity that can be cultivated through learned skills.
Creativity: Flow and the Psychology of Discovery and Invention by Mihaly Csikszentmihalyi. An excellent book showing the results of research into the psychology of creativity – specifically of the creative process of innovators in many fields but applicable to the arts.
The Artist’s Way by Julia Cameron. Not a book about creativity but a series of exercises designed to free you to be more creative.
On music and spirituality
The Musician’s Soul: A Journey Examining Spirituality for Performers, Teachers, Composers, Conductors, and Music Educators by James Jordan. Takes music as a path to personal growth and shows that connecting the two leads to more moving performances. Takes a (not too sophisticated) psychological view that illuminates the connection.