Hello! I am going through your question.In my opinion related to your symptomps the most possible diagnosis is mastitis that is very rare in male. But, I think in this case should do a differential diagnosis with an inflammatory breast cancer. So, to verify the diagnosis I think you need to do a physical examination, taking medical history by a doctor and some lab test ( full blood test) . In this situation, if verify that is mastitis I usually prescribe, ibuprophen and antibiotics like ampicillini or amoxicilini ( if you are not allergic) based on the most probably bacteria can caused mastitis ( staphylococcus, streptococcus). I hope my answer help you. I wish you a quick recovery.