Yes, absolutely, anger begins in childhood.
Sometimes when things that matter so much to us, whether they be temporal needs or spiritual perceptions, are not provided in a timely manner we become discouraged. We are fearful that these disappointments will go on for a period of time, or that they will never be achievable. This fear comes from trying to trust in self or others instead of trusting in God. It comes from not waiting on God and his time schedule. The safety and security that we long for at times can only be supplied by God.
This fear, along with our desire to fulfill our own needs, will lead to rebellion. We get angry toward anyone who stands in our way or who does not go along with our personal agenda. We begin to look only for those who can help us fill this personal agenda we have made for ourselves. Before long we make demands that cannot be fulfilled.
Even though we despise it, we have a tendency to hang on to our anger because the anger hurts less than the fear we feel. Eruptions of anger serve to dull the pain that is deep within us. In a false sense of the word, it gives us a feeling of security that we are controlling our own situations.