Ethinyl estradiol cyproterone tablets eat chest swelling pain may be drug side effects or breast disease caused by. 1. drug side effects: ethinyl estradiol cyproterone tablets are mainly composed of estrogen and progesterone, after taking the drug will lead to increased levels of hormones in the body, the mammary glands in the estrogen and progesterone stimulation of breast swelling and pain symptoms, generally stopping the drug after the swelling and pain in the breast symptoms will gradually reduce and disappear. This is a side effect caused by the drug and can be temporarily observed. 2. Breast disease: women who suffer from breast hyperplasia or breast tumor will be aggravated after taking medication, which will cause breast swelling and pain symptoms, generally the swelling and pain symptoms are serious, accompanied by hard lumps or nodules and other phenomena. The cause of breast pain can be clarified by combining with breast ultrasound or mammography to give treatment.