Breast cancer. Normal physiological swelling and tenderness Your breasts change throughout your menstrual cycle each month because of your hormones. At least half of all women who have periods will have some pain, tenderness and lumpiness in their breasts at some time in the month. This is usually most obvious in the week before your period. It quickly goes when your period starts. When this pain and lumpiness cause problems, the condition is known as fibrocystic change.
The lumps will shift location and change, getting larger and smaller as your breast empties and fills. Lumps that come and go are not a cause for any concern. Mastitis If engorgement or blocked ducts are not relieved promptly a mother may get symptoms of mastitis—inflammation of the breast. This will be very painful and may cause mum to feel generally unwell with flu type symptoms such as feeling achey and shivery.
I hope this is helpful! Wishing you all the best. I am
Gear and Products Your nursing breasts may feel lumpy at times. At other times during your breastfeeding experience, you may notice small, tender lumps in your breasts. These are most likely plugged milk ducts.