Thank you for the query.
is very sketchy test which is performed only to rule out bowels obstruction and perforation. Other possible diseases wont be visible in this test.
If your pain appears after an hour or two after a meal, peptic ulcers should be considered.
If your is more in the lower abdomen and you do suffer from constipation, diverticulitis
can be the reason.
If your pain radiates to the back, pancreas disease should be ruled out.
Such pain can also appear due to urinary tract infection
, burning while urinating appears), ovarian cyst
, large intestine disease (like polyps or even a cancer - this is more possible if you are 50 or more).
I suggest you to visit gastroenterologist, have physical examination, blood tests, liver tests, urine analysis, amylase, abdominal ultrasound. Upper GI endoscopy should be performed if peptic ulcers are possible and colonoscopy if diverticulitis seems possible.
Hope this will help.