there are many causes of shyness in children
whenParents or one of the parents is plagued by Shyness. - parent's own self-depreciation carry them to despreciate or not trust their child.
Parents-or one of them behave agressively. This give to the child a vision of others as potentially hostile.
Silent or public humiliating experiences - This situation stop or distorts the way that child is being developed.
Critical relatives - Some families have a very critical culture. This posture can be open, direct (towards itself) or indirect (towards outside).
Shaming family problems - It is common for children and teenagers to feel ashamed, for instance, while their parents are separating. This can be overcome in a short time or may longer as an way of self-depreciation. Family problems or somes other things,can also cause this damage.
Unaffectionate, cold families - In some families the members do not express their feeling or do it very seldom, especially tender loving care and joy for the accomplishment of their members.All this can contribute indirectly to Shyness, insofar it does not help to develop a personal perception of one's capacity for accomplishment or feeling of being estimated,loved and respected by others.
Finally l think that shyness leads the major cause of personal and social life problem.