I'm a 24 year old female not sexually active but experiencing period like cramps but not my period the last few days 1/2 hour at a time what's wrong!?

Pelvic pain: Pelvic pain is complex as there are several organs in the pelvis. The ovaries, fallopian tubes, uterus, cervix, bladder, appendix, intestines, colon and rectum can all be the source. Pelvic pain requires and examination to help organize the evaluation. Since you have a 28 day cycle we would expect your period around day 28 unless you got pregnant