Why do I get shoulder pain during my period?

Shoulder pain that predictably shows up around your period can be a “referred pain” pattern—meaning irritation somewhere else is felt in the shoulder. One important (and often overlooked) explanation is endometriosis on or near the diaphragm, the muscle that separates your abdomen from your chest. When endometriosis involves the diaphragm, symptoms can include right-sided shoulder or arm pain, upper abdominal or chest discomfort, and pain that may worsen with deep breathing or coughing, often clustering around menstruation.

Because diaphragm and thoracic (chest) involvement are less common, they’re frequently missed—especially if pelvic symptoms get all the attention or if imaging doesn’t clearly show the cause. In rare situations, endometriosis can extend into the chest and be associated with cyclical chest pain, shortness of breath, or even recurrent lung collapse around periods. If your shoulder pain is cyclical—especially if it’s right-sided or comes with chest/upper-abdominal symptoms—our team can help you connect the pattern, evaluate for diaphragmatic or thoracic involvement, and discuss options such as targeted imaging and, when appropriate, minimally invasive surgical evaluation and excision by an experienced team.