A little bit of pain in the breasts of an eight-year-old girl may be a normal phenomenon, or it may be caused by mastitis, breast trauma, and other reasons such as breast cancer. 1. Normal phenomenon: the girl’s body sex hormone may become more when she is eight years old, at this time the girl may appear breast development, so there may be breast not swelling pain, but press a little pain performance. This may be a normal physiological phenomenon and does not require treatment. 2. Mastitis: The mammary glands of eight-year-old girls may develop, and if there is bacterial infection of the mammary glands, blockage of the mammary glands, or inverted nipples at this time, it may lead to breast lumps and pain in the mammary glands. If you press on the mammary glands, there may be a little pain. 3. Mammary gland trauma: Some girls’ mammary glands will develop when they are eight years old, but they are not swollen and painful. If there is a trauma to the mammary gland at this time and pressure is applied to the mammary gland, there may be a little pain. 4. other: eight-year-old girl breast development a little bit not swelling pain, but press a little pain is also considered to be breast cancer, breast hyperplasia and other diseases. Once the eight-year-old girl breast abnormalities, we should promptly consult a doctor to clarify the cause of the disease, and then follow the doctor’s instructions to carry out the appropriate treatment.