There are many reasons why breasts become bigger and swollen, which can be analyzed from the following points: 1, pubertal development, boys and girls have hormonal instability during puberty, causing the feeling of swollen and painful breasts, which will disappear after puberty. 2, breast injuries, such as chest bumps, damage to breast tissue and hematoma resulting in painful swelling of the breasts, can be applied cold first and then hot, paste blood circulation and blood stasis.