Breast tenderness can happen as a result of both disease processes and normal changes. Breast tenderness can be worsened with pressure (in some cases, very little pressure can be a reason) or it may not be affected by pressure at all and this depends on the cause. Tenderness of breasts can be associated with breast swelling. Also, tenderness of breasts can be associated with either reproductive changes (like premenstrual tension, premenstrual syndrome, or early pregnancy) or hormonal changes. 
Also, dietary changes, like large amounts of caffeine can lead to tenderness of breasts . The usage of estrogen medications (such as birth control pills) can be a cause too . The weight gain which is leading to breast ptosis (known as drooping) can cause breast tenderness or a primary disorder in which breast tenderness is just one of the several symptoms. Some of the main causes for tenderness of breasts are including a malignant or benign tumor, breast abscess, serious disorders, such as ectopic pregnancy (this is a life-threatening pregnancy, which is growing outside the uterus), mastitis (this is a breast inflammation and it is often experienced while breastfeeding) and fibrocystic breast disease (these are benign breast changes).
The tenderness of breasts which is cyclical can be related to reproductive cycles or hormonal changes. In some cases, the occasional usage of – the – counters medications, such as ibuprofen or a simple change in the diet can help to alleviate the pain. But, also there are some symptoms (like tenderness with no relation to your menstrual cycle, tenderness lasting more than two weeks, and persistent pain), which can indicate a more serious condition, such as breast cancer or breast abscesses.
Tenderness of Breasts Symptoms:
The tenderness of breasts can be accompanied by other symptoms, which depend on the underlying condition, disorder, or disease.
- Breast symptoms that may happen along with breast tenderness: The tenderness of breasts can be accompanied by other symptoms that are affecting breasts, such as
- Redness, warmth, or swelling
- Breast lump
- Nipple discharge or tenderness
- A change in the look and feel of the skin of the breast, such as dimpling or puckering
- A change in the size, shape, or appearance of the breast
- Lower reproductive tract symptoms may happen with breast tenderness: The tenderness of breasts can be accompanied by other symptoms that are affecting the lower reproductive tract, such as
- Cramping before or during the menstrual cycle
- Abdominal pain or cramping in cases of ectopic pregnancy (life-threatening pregnancy growing outside the uterus)
- Abdominal, pelvic, or lower back pain during the menstrual cycle
- Abdominal swelling, distension, or bloating
- Other symptoms that may happen along with breast tenderness: The breast tenderness can accompany symptoms that are related to other body systems, such as the digestive system or immune system, like:
- Nausea with or without vomiting is related to either possible early or ectopic pregnancy (the life-threatening pregnancy, that is growing outside the uterus) or premenstrual pain
- Symptoms that may indicate a serious condition: There are some symptoms, which can indicate a serious condition, such as
- Significant decrease in urine output
- Fainting or change in level or lethargy or consciousness
- Difficulty breathing
- Confusion or loss of consciousness for even a brief moment
Often, breast tenderness is a result of the natural menstrual cycle, because the estrogen gradually peaks just before the mid-cycle, causing the breast ducts to enlarge.  In addition to this, the progesterone levels may peak near day 21 and 28 – day cycle, which is causing growth in the milk glands. Both are contributing to the normal tenderness of breasts and premenstrual swelling, which is experienced to some degree by most women. Also, these hormonal changes can cause tenderness of breasts in early pregnancy too . Tenderness of breasts can be caused by primary disorders, physical breast changes, lifestyle factors (such as medications and diet), and breastfeeding.
 Hashim MS, Obaideen AA, Jahrami HA, et al. Premenstrual syndrome is associated with dietary and lifestyle behaviors among University students: A cross-sectional study from Sharjah, UAE. Nutrients. 2019;11(8):1939. doi:10.3390/nu11081939
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 Crandall CJ, Aragaki AK, Chlebowski RT, et al. New-onset breast tenderness after initiation of estrogen plus progestin therapy and breast cancer risk. Archives of Internal Medicine. 2009;169(18):1684–91. doi:10.1001/archinternmed.2009.303
 Eunice Kennedy Shriver National Institute of Child Health and Human Development. What are some common signs of pregnancy? 2017. Retrieved from www.nichd.nih.gov/health/topics/pregnancy/conditioninfo/signs