What Might Have Caused Sudden Severe Pain Below My Navel With Chills That Improved The Next Day?

Had severe pain to right and below navel with cold chills overnight Sunday after eating dinner. Did not vomit or have diarrhea. Have only drank fluids, no problems urinating, no blood on stool. But still have some tenderness but no severe pain. Generally feeling better today and rested all day Monday. Took one aleve for a slight headache. Should I worry about what the pain was from? I am a very healthy person.