<s>[INST] My husband noticed a mildly painful lump behind his left ear yesterday and tonight it has grown in size and the pain has gotten worse. He is allso experianceing ringing in his earss and if you touch the lump you can feel it throb. What could be causing this and should we make a trip to the er [/INST] Hi, dear. I have gone through your question. I can understand your concern.  You may have sebaceous cyst or some other lesion.  Consult your ent doctor and go for excision biopsy and thrn histopathological examination. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using health care magic. Wish you a very good health. </s>