Hard lumps in both breasts may be due to breast enlargement, breastfeeding, or pre-physiological reactions. When you have breast enlargement, you will have painful lumps in your breasts, most of which are in both breasts. Mammary gland hyperplasia needs to be treated with medication, and in severe cases, surgery is required. If the milk is not discharged in time during breastfeeding, the remaining residual milk will cause the breast to become blocked and form hard lumps in the breast which will become harder and harder if not unblocked in time and may cause fever. Most women will have breast pain before the physiological period and some women will have hard lumps. In addition, breast diseases may also cause this symptom. Therefore, it is best to go to the hospital for a comprehensive examination after the appearance of this symptom, and then treat it according to the examination results.