What can a pain on your lower right abdomen mean?

Many possibilities. Possible causes of right lower abdominal pain include appendicitis, ectopic pregnancy, ovarian cyst, endometriosis, inguinal hernia, seminal vesiculitis, GI obstruction, renal infection or stones & gastroenteritis just to mention a few. If you have severe abdominal pain then urgent medical evaluation is indicated. Abdominal pain with change to stool pattern warrants evaluation.