There are many possibilities in you. Most importantly, I feel Appendicitis
has to be ruled out here.
In addition, there may be stone in the urinary tract
I suggest you to get an ultrasound
scan of the abdomen and look for any of these.
The treatment will depend on the cause.
If the ultrasound is normal, then IBS (Inflammatory Bowel Disease
) may be considered too.
I hope this helps you.