<s>[INST] Small pea sized lump on Mastoid Bone that is as hard as a bone and I cannot tell if it moves, if it does it isn t moving much. Little to no pain when I press on it, more pressure than anything. Should I feel alarmed? Is this something worth going into the doctors office for? Thanks! [/INST] Hi, dairy have gone through your question. I can understand your concern. You may have some enlarged lymph node due to reactive hyperplasia or mastitis.  You should take a course of antibiotics.  If it doesn't respond to treatment then biopsy diagnosis is advisable. Consult your doctor and take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using Chat Doctor. Wish you a very good health. </s>