27 yrs old female with acute onset of severe continues abdominal pain

27 yrs old female with acute onset of severe continues abdominal pain just below umblicus not radiating anywhere, gripping in nature, not associated with fever, vomit or abdominal distension, releived by pain killers not by spasmolytics.

Vital signs are normal,
Hypertrophied uterus on ultrasound due to recent pregnancy with normal delivery 4 days back.
Tenderness below umblicus.
Patient had a normal deleivery 4 days back.
Lifted weight of 10 kg before 4 hours of pain,
Not constipated,
No burning micturition
No anemia, no jaundice, no lymphadenopathy.