<s>[INST] There is an egg (bump) on the back of my head, right side. I've had this bump there for many years and did does hurt sometimes but this morning I got up and it was throbbing. It doesn't hurt unless I apply pressure or turn my head to the left. Should I be worried or is it hurting because I slept wrong? [/INST] Hi,It seems that you might be having Sebaceous cyst on head.Now it seems to be infected giving this trouble.Consult surgeon and get examined.Meanwhile you may try one antibiotic medicine course to get temporary relief from pain and infection.Do not press the lump.Ok and take care. </s>