Inflammation of the colon may cause pain in your lower right abdomen. The pain of appendicitis may also spread to the lower right abdomen. I am also including a link that goes into more detail on Appendicitis, please do read that over as well.
Other causes that it can be in females is ovarian cyst or possible ectopic pregnancy. Since this has been going on for several days, it is best to see your doctor at this point, as generally an ultra can help determine what is going on.
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