Your pain abdomen most common cause seems to be
kidney stone as it is also in back with abdomen
second most common cause is appendicitis but that is only in lower abdomen associated with fever and vomitting
Next Steps
You should get a sonography(ultrasound) of abdomen done...it will confirm your diagnosis
delaying the diagnosis may harm you in long run
Health Tips
drink 3 ltrs of water per day
avoid spicy food
dont delay your diagnosis