Causes of Left Breast Pain

A List of Common Breast and Non-Breast Related Causes

Woman consulting doctor with chest pain
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When there's a pain in your left breast, you may instantly think of breast cancer, a severe infection or a heart attack. 

Let's learn more about the common causes of left breast pain, both breast-related and non-breast related.

Breast Causes of Left Breast Pain

Your breasts are draped in sensitive, elastic skin that protects nerves, blood vessels and connective tissues as well as ducts and lobes for producing breast milk.

If you've had a breast injury, you can expect bruising and an ache that will persist until the skin and underlying tissues have healed.

After any type of breast surgery - augmentation, reduction or reconstruction - your breast will hurt as incisions heal and scar tissue develops. 

In addition, several benign but painful conditions can develop inside your breast milk system. An abscess may occur under your nipple or areola, milk ducts can become clogged and infected, causing mastitis or ductal ectasia. Breast cysts and fibroadenomas may grow and crowd your milk system or connective tissue, creating aches and pains.

Hormone changes may also cause breast tenderness, especially when levels change during a woman's menstrual cycle or while on hormone pills, like oral contraceptive pills or hormone therapy. Hypothyroidism — characterized by low thyroid hormone — may also be linked to benign breast disorders that cause breast pain.


When you suspect breast infections or inflammation, visit your family doctor or gynecologist. You may need to take antibiotics or other prescription medications to clear up the problem. Finally, whenever you find breast lumps or bumps that are not related to your menstrual cycle, consult with your family doctor right away to get a clear diagnosis and proper treatment.

Left Breast Cancer

The Surveillance, Epidemiology and End Results (SEER) study collected data from 250,000 women and men who were diagnosed with breast cancer. Between the years 1973-92, SEER researchers found that about 5 percent more of all breast cancers start in the left breast of female patients. Male breast cancer patients had an even chance of developing cancer in either breast. 

Nevertheless, when you do your monthly breast self-exam, don't focus on your left breast alone, but be sure to give equal attention to right and left breasts. Stay current with your breast screenings and annual physical exams. Breast cancer doesn't usually cause any breast pain, but in a few cases, it may do so.

Non-Breast Causes of Left Breast Pain 

Sometimes when pain happens, it is hard to tell exactly what hurts and where the pain is centered. When pain hits you on the left side of your chest, you may think it is left breast pain, but the pain may actually be beneath your left breast.

Below your breast there are chest wall muscles that may spasm during times of anxiety and stress, causing pain that may last just a few seconds or several days.

Pain from tense chest wall muscles can occur on the left side only, or on the right. Likewise, if you have a pulled chest muscle or an injury to the left chest, aches and pains may result.

In addition, your heart is beneath your left breast. Breast pain can indicate a heart attack — this is very serious and requires immediate medical attention. While the typical symptoms of a heart attack include a squeezing pain or pressure in the chest area, accompanied by lightheadedness or sweating, some people — especially women — have only mild or atypical symptoms. These may include nausea and vomiting, feeling short of breath, or back or jaw pain.

Since your esophagus runs below your left breast, gastroesophageal reflux disease can occasionally feel like left breast pain. A related condition, hiatal hernia, may cause similar symptoms.

If what feels like left breast pain is actually in your cartilage, than costochondritis in your sternum (breastbone) can cause pain on the right or left chest when cartilage becomes inflamed.

Fibromyalgia may also cause pain anywhere in your body, and chest pain is not uncommon. Fibromyalgia can affect muscles, joints and connective tissues, creating generalized pain or focused pain.

Pneumonia or a blood clot can also cause left-sided pain since your lungs are in your chest area underneath your breasts.

What Should I Do?

There are a number of causes for breast pain, some more serious than others. The only way to know is to seek medical evaluation. 


American Heart Association. (2015). Heart Attack Symptoms in Women. Retrieved October 12th, 2015.  

Bhargay PR et al. Prevalence of hypothyroidism in benign breast disorders and effect of thyroxine replacement on the clinical outcome. World J Surg. 2009 Oct;33(10):2087-93.

Breast Pain; Pp. 77-85. Dr. Susan Love's Breast Book. Susan M. Love, M.D. Fifth Edition, 2010.

McConaghy JR & Oza RS. Outpatient diagnosis of acute chest pain in adults. Am Fam Physician. 2013 Feb1;87(3):177-82.

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