<s>[INST] hi i have had gastroenthistias and viral bacterial infection since january all has calmed since then but now i have got a bup on my head scalp somehow i havent hurt myself if i touch it it will hurt and sometimes when i move my head gives me sudden pain what is this [/INST] Hi, dairy have gone through your question. I can understand your concern. You may have some enlarged lymph node, soft tissue tumor like lipoma or neurofibroma or some benign cyst like Desmond cyst. You should go for fine needle aspiration cytology. It will give you exact diagnosis. Then you should 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>