Large breast can place excess weight on your chest thereby affecting the curvature of your spine and leading to upper back pain. Without enough support from the surrounding muscles and the rest of the body, the weight of the breasts can cause severe pain, making it difficult to maintain good posture, and may even lead to spinal deformity. Some women becomes conscious of the size of their breast and this makes them to hunch forward trying to hide their chest from view - however, this may even worsen their back pain.
Very large-breasted women sometimes have to grapple not only with chronic pain in their backs and necks, but also with bra straps that dig into their skin and limitations on the activities that they can comfortably engage in.
Back Pain and Breast Size: Research Findings
Studies have shown that there can be a chain reaction of painful symptoms resulting from large breasts, as the body compensates for an abnormal position in one part of the back by shifting the position of another. Breast cups size D and above can cause upper back pain by altering the curvature of the spine, according to research, and can have an important impact on posture.
This is what you can do to ease or prevent the pain
If you suffer from neck or upper back pain caused by large breasts, series of helps are available.
 .  Customized bras and sports bras. Because they are specially designed, these types of bras can help distribute and support the weight of large breasts — especially for women with narrow backs, who have a more concentrated distribution of weight than women whose backs are wider.
 .  Physical therapy and exercise. Working with a therapist or personal trainer can improve posture and encourage weight loss in women who are overweight or obese.
 .  Medication. Taking an occasional over-the-counter pain reliever (such as ibuprofen or aspirin) when upper back pain strikes is just fine. And your doctor can prescribe stronger medication to "get you over the hump" of more severe pain caused by large breast size. But keep in mind that painkillers for back pain caused by large breasts are not intended as a long-term solution.
 .  Breast reduction surgery. Often recommended to women with upper back pain caused by large breasts, breast reduction surgery may be the only way to permanently resolve the issue.
Research published by the American Society of Plastic Surgeons found that, prior to breast reduction surgery, half of 179 women with breasts size DD or larger had almost constant upper backpain or pain in their necks, shoulders, or lower backs. After the surgery, only 10 percent of women had these symptoms.
Bottom line: If you are suffering from upper back pain due to large breasts, talk with your doctor. Together, you can put together a plan that will be effective for you.