The right nipple of the male nipple has a lump, pressure pain, considering that may be related to mastitis, breast hyperplasia, breast cancer and other diseases. 1. Mastitis: not paying attention to personal hygiene or nipple trauma is likely to lead to nipple infection, inducing the onset of mastitis, local redness, swelling, pain and other clinical symptoms. 2. Mammary gland hyperplasia: The abnormal level of estrogen and progesterone in the male body may stimulate the proliferation of breast tissues, resulting in a lump in the nipple of the right breast of the male, which is painful when pressed. 3. Breast cancer: men also have the possibility of getting breast cancer, and the occurrence of this condition may be related to genetic factors, gene mutation, and environmental factors. Malignant cells grow and multiply continuously and form lumps, leading to pain when pressed. The lump in the nipple of the right breast of a man, which is painful when pressed, may have other causes such as trauma. It is recommended to go to the breast surgery department of the hospital as soon as possible and cooperate with the doctor to receive treatment.