Breasts are normally soft, once you feel a localized hard lump, you should go to the hospital in time for an examination, considering that it is caused by breast hyperplasia and mastitis. Breasts are mainly made of mammary tissue and fat accumulation, the whole breast feels soft to the touch and does not show pain or hard lumps. Before menstruation, the hormone level changes, women’s mammary interstitial lobe edema, mammary follicles produce hyperplasia, hyperplasia lumps in the pre-menstrual period will be bigger, and cause localized pain. After menstruation, the hormone level retreats and the swelling disappears. When inflammation occurs in the breast area, it will lead to chest pain, and there will be hard lumps when touched by hand. Mastitis is caused by cracked nipples, damage, and bacterial invasion of the milk ducts causing inflammatory lumps in the breast area, and regular ultrasound examinations of the chest in the hospital can keep you informed of the chest.