<s>[INST] 2 days ago, I Started off with left side abdominal pain that ends up goin to my lower right quadrant and across the lower abdomen above pelvic area. Followed with a severe headache in the lower back of my skull. What could this have been? It was the most intense headache and abdominal pain I have ever had. Also I had a fever. I could not even move without intense pain.  I didnt have any nausea or vomiting just pain. [/INST] Hi ! Good morning. I am Chat Doctor answering your query. Most likely you have some intra-abdominal infection amongst which appendix is on the top of the list, and next it might be a UTI (Urinary tract infection) or a pelvic infection in case of females. Whatever be the cause, it needs a clinical assessment of the problem with related investigations, and so you have to show yourself to your family physician/the nearest ER of a hospital at the earliest. I hope this information would help you in discussing with your family physician/treating doctor in further management of your problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing Chat Doctor to clear doubts on your health problems. Wishing you an early recovery. Chat Doctor. </s>