As a man you can have female breast development. This is also called gynecomastia. In addition to feelings of shame, gynecomastia can also cause pain. There are several causes for breast formation in men including obesity and side effects of medication.
Changes in hormone production or metabolism can also cause breast development.
Breasts can also occur in boys during puberty but after 2 years this usually disappears by itself. If this is not the case, then a surgical correction is necessary.