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The origin of pain can either be in the abdominal muscles or inside the abdomen. The place which you describe can become painful in case of an abscess or an infected hematoma in abdominal muscles. It could also be cystitis, urinary tract infection, diverticulitis or inflammatory bowel disease. A urine examination is definitely required. In women it can also be due to uterine fibroids, pelvic inflammatory disease or polycystic ovary. Please consult a gynecologist regarding this.
Hope these tips help. Please let me know if there is any thing else and do keep me posted. Take care!