- Breast tenderness caused by normal hormone fluctuations is common and not a cause for concern.
- Causes like breast cysts and deep bruises usually don’t require treatment and go away on their own.
- If you have redness, swelling, or an inverted nipple, see your doctor as soon as possible.
- Visit Insider’s Health Reference library for more advice.
It’s normal for your breasts to be sore sometimes. But while some causes of breast tenderness are rather innocuous — like an ill-fitting bra or normal hormonal fluctuations — sore breasts can also be a sign of something more serious, like breast cancer.
Here are eight possible reasons why your breasts may feel tender.
1. You’re about to get your period
Fluctuations in sex hormone throughout your menstrual cycle affect your breasts in two major ways:
- Your estrogen levels rise in the first half of your cycle, between the end of your period and ovulation, which causes your breast ducts to swell.
- Your progesterone levels rise during the second half of your cycle, between ovulation and the start of your next period, which causes milk glands to form in your breasts.
Both of these hormone changes can trigger breast pain, but your breasts will usually be most tender just before your period starts.
Signs that your breast pain is linked to your period include:
- The pain comes around the same time every month.
- Along with soreness, your breasts feel more lumpy than usual — this may be a sign that your milk glands are enlarged.
- The pain often occurs in the upper, outer region of your breast, or around your nipple, says Monique Swain, MD, Director of the Obstetrics and Gynecology Residency Program at Henry Ford Health System.
- You have other premenstrual symptoms like bloating, fatigue, or mood swings.
- The pain goes away once your period starts.
2. Your bra doesn’t fit properly
Your breasts can get sore from wearing the wrong size bra — both too small and too big bra sizes can cause issues. But “a well-supportive bra can help to reduce breast pain,” Swain says.
According to Swain, a good bra can help by:
- Keeping your breasts from moving too much during exercise.
- Lifting your breasts upward to relieve tension on the cooper’s ligaments that support your breasts.
An ill-fitting bra can cause soreness by:
- Compressing your breasts too much.
- Having an underwire that digs into your skin rather than laying flat.
Alberta Health Services offers a guide for how to accurately measure your bra size and what to look for in a good fit.
3. You have breast cysts
Breast pain can also be caused by breast cysts, which are plugged-up ducts that fill with fluid.
Large cysts can be painful, “because as a cyst gets larger, it expands the wall of the duct, stretching it and creating tenderness,” says Therese Bevers, MD, a professor of clinical cancer prevention at the University of Texas.
Two signs that you may have a cyst are:
- You have a smooth, round lump that is easily movable.
- You have clear, yellow, or brown discharge from your nipple.
Cysts usually don’t require treatment and often go away on their own. But if they’re painful, you can see your doctor to have the fluid drained.
4. You have a deep bruise
If your breast gets bumped or injured, you can develop a deep bruise that isn’t always visible.
If one of your breasts is tender and you think you may have hurt it, you can look for signs like:
- You don’t feel any new lumps or masses.
- It starts to feel better after a few days of not touching the breast at all.
5. You have a milk duct infection
Particularly if you’re breastfeeding, it’s possible for one of your milk ducts to become infected. This can cause “inflammation and swelling in the duct system and surrounding breast tissue which can lead to severe pain and discomfort,” Swain says.
Milk duct infections can start suddenly and may come with symptoms like:
- Redness and swelling
- Breast feeling warm to the touch
- A burning feeling, especially while breastfeeding
- Feeling generally sick or having a fever
If you think you may have an infection, see your doctor as soon as possible to determine if you need
6. You have a rare type of breast cancer
“Most breast cancers don’t cause tenderness,” Bevers says. But a rare form of cancer called inflammatory breast cancer causes pain when the tumor invades your skin.
“This causes an inflammatory process in the skin, which can cause tenderness,” Bevers says.
Other symptoms of inflammatory breast cancer include:
- Swelling in only one breast
- Purple or red skin color
- Breast skin thickening or dimpling to look like an orange peel
- Inverted nipple
Inflammatory breast cancer is very rare, making up only 1%-5% of breast cancers, but if you have these symptoms, you should see your doctor right away.
7. You’re pregnant
In the first few weeks of pregnancy, your body produces high levels of estrogen and progesterone — this causes your milk ducts to swell and prepare for breastfeeding.
Your nipples may feel especially sore and you may notice that your breasts grow one or two cups sizes during the first six to eight weeks.
Breast tenderness may come with other early pregnancy symptoms like:
- A missed period
- Urinating more often
8. You take certain medications
There are several types of drugs that can trigger breast pain or tenderness. This can include:
- Blood pressure medications like methyldopa (Aldomet) and spironolactone (Aldactone)
- Certain diuretic medications
- Birth control pills
- Hormone treatments for issues like infertility
- Psychiatric drugs like chlorpromazine
If your breast pain is severe, you can talk to your doctor about adjusting or switching your medications.
Breast pain is very common and is rarely caused by a serious illness like cancer. In many cases, breast tenderness is triggered by natural changes in your hormones or by a minor issue like a cyst or bruise.
“However, if you have any skin changes, a lump, nipple changes, and/or discharge associated with breast pain, you should see a doctor immediately,” Swain says.