Breast pain is extremely common, and in most cases it’s tied to normal hormonal fluctuations rather than anything dangerous. Only about 5% of breast cancer cases involve pain as the primary symptom, so while it’s worth paying attention to, breast pain on its own is rarely a sign of something serious. The cause usually falls into one of two categories: cyclical pain linked to your menstrual cycle, or non-cyclical pain caused by something else entirely.
Cyclical Pain: The Most Common Cause
The most common type of breast pain is hormonal. It follows your menstrual cycle, often starting around ovulation and lasting until your period begins. You might notice both breasts feel heavy, swollen, or tender, sometimes with a dull ache that radiates into your armpits. This happens because estrogen and progesterone stimulate breast tissue during the second half of your cycle, increasing the size of milk ducts and glands and causing your breasts to retain water.
Some research suggests that people who experience more intense cyclical pain may have a relative imbalance between estrogen and progesterone, or differences in how prolactin (a hormone involved in milk production) behaves. Stress can also amplify the pattern, since it shifts hormone levels in ways that make breast tissue more reactive. If you’ve noticed the pain gets worse during particularly stressful months, that’s not a coincidence.
Cyclical breast pain tends to ease once your period starts and often improves after menopause, though hormone replacement therapy can bring it back. If you’re on oral contraceptives or recently started them, that’s another common trigger.
Non-Cyclical Pain: Other Reasons Your Breast Hurts
If the pain doesn’t follow a monthly pattern, stays in one specific spot, or only affects one breast, it’s likely non-cyclical. This type is less common and has a wider range of causes.
A direct injury or blow to the breast can cause lingering soreness, sometimes for weeks. Cysts, which are fluid-filled sacs in breast tissue, can cause sharp or aching pain in a specific area. If a cyst is the culprit, draining the fluid typically resolves the pain quickly.
Infections also cause breast pain. Mastitis, an infection in a blocked milk duct, causes tenderness, swelling around the nipple and areola, and sometimes fever. It’s most common during breastfeeding but can happen at any time. Another condition called mammary duct ectasia occurs when a milk duct widens and becomes clogged, potentially leading to nipple discharge, skin color changes around the areola, and pain that worsens if infection sets in.
Pain That Isn’t Actually Coming From Your Breast
Sometimes what feels like breast pain is really coming from the chest wall beneath. Costochondritis, an inflammation of the cartilage connecting your ribs to your breastbone, is one of the most common culprits. It typically affects the upper ribs on the left side and produces a sharp or pressure-like pain that gets worse when you take a deep breath, cough, sneeze, or twist your torso. Because the pain sits right behind breast tissue, it’s easy to assume the breast itself is the problem.
Arthritis in the chest cavity or neck can also radiate pain into the breast area. If the pain changes with movement or posture rather than with your cycle, a musculoskeletal cause is worth considering.
Medications That Cause Breast Pain
Several types of medication can trigger breast tenderness as a side effect. Hormonal medications are the most obvious, including oral contraceptives and estrogen replacement therapy. But the list extends further: certain antidepressants (SSRIs like fluoxetine), some antipsychotic medications, certain blood pressure drugs, and even some diuretics (water pills) are known to cause breast pain. If the timing of your pain lines up with starting or changing a medication, that connection is worth exploring with your prescriber.
A Well-Fitting Bra Makes a Real Difference
This sounds simple, but the evidence behind it is surprisingly strong. Studies have found that wearing a properly supportive bra relieves breast pain in up to 85% of cases. One study compared a sports bra to a prescription medication commonly used for breast pain: the sports bra worked in 85% of participants, while the drug worked in only 58%. Reducing excessive breast movement through better support is the key mechanism.
The catch is that finding the right fit isn’t always straightforward. Research has found that many people struggle to purchase an appropriate bra even after a professional fitting. If you’re experiencing regular breast pain, it’s worth getting fitted and specifically trying a supportive sports bra during the days when pain is worst.
Signs That Need Medical Attention
While breast pain alone is rarely a red flag, certain accompanying symptoms change the picture. Pay attention if you notice a new lump in your breast or armpit, thickening or swelling of part of the breast, dimpling or puckering of the skin, redness or flaky skin on the nipple or breast, nipple discharge (especially if bloody), the nipple pulling inward, or any change in the size or shape of one breast.
If your pain is focal (concentrated in one specific spot), non-cyclical, and persistent, imaging may be appropriate. For people under 30, ultrasound is the preferred first step because denser breast tissue makes mammograms less accurate at younger ages. For those 30 and older, both mammography and ultrasound are considered appropriate starting points. If you’ve had a mammogram within the last three to six months, your doctor may skip straight to ultrasound.
Pain that stays in one place for weeks, gets progressively worse, or comes with any of the symptoms listed above is worth getting checked. Pain that comes and goes with your cycle, affects both breasts, and has no other accompanying changes is, in the vast majority of cases, your hormones doing exactly what hormones do.