<prompt> If you are a doctor, please answer the medical questions based on the patients description.I have a knot on the back of my head, it appeared about 3 days ago. It started out small and barely noticable. Now it is about 12 inch long and 14 inch wide. It is very painful and extremly painful when it is touched. Even some area around the knot is painful. I did not hit my head or can think or any other cause to where this knot came from. I had a nurse look at it to day, she had no idea what it could be but, ruled out pimple or infected hair folical. I am having headaches and slight trouble focusing, which in normal for me when I dont get enough sleep. But, it is torture to lay my head down to rest, and if I postion my self where I am not laying on it, it is still painful and very uncomfortable. I am more concerned with what this knot is and how to get rid of it than anything else. Please help.  <response>: Hi, DEar, thanks for your query to Chat Doctor. I studied your query in depth.1-In My opinion the painful knot on the back of your head appears to be a spider biteinsect bitebedbug bite-with infection-cellulitis at the back of your head.2-Or it could be unnoticed early progressive folliculitis, which your nurse missed.3-I would suggest you to check with doctor, who would CBC, X-ray skull, for to rule out the unforeseen cause of the headache with the painful lump in your back of the head.4-Hope this would solve your query.5-Wellcome for any more questions on new or this subject also... Have A Good Day.!! 