This might be a parenting as well as problem with the environment. You have to see a psychologist to diagnose the issue. Confidence in children is usually a Presteigne related issue. But several times it can be due to past bad experiences with friends teachers etc. We have to check before coming to a conclusion.
Next Steps
See a psychologist and make plan for yourself and your child.
Health Tips
Many times such issues arises due to wrong parenting style. Even if parents intentions are not bad their way of expressing might be a problem. Make sure you work on some of the skills before just coming to conclusion about your child.