Hi.
Thanks for your query.
Noted the history and understood the concerns.
Stomach pain for 4 months,
tenesmus as we call for pain in abdomen before and after passing motion, no stool coming out in spite of sitting for a long time can be due to IBS, that is
irritable bowel syndrome.
This is so as you have already gone through some most important investigations like
Ultrasonography, Barium test, CT scan of abdomen and are normal.
What remains to be done are as follows:
Colonoscopy and biopsy.
Test of stool for three consecutive days.
Tests of blood:
thyroid, liver and kidney functions.
Also note the foods and beverages that instigate or enhance the problems.
Use anti-spasmodic with anti-stress medications.
Use Yoga and such Naturotherapy for control.of stress and anxiety.Change of lifestyle is very important. This for suitable life which every one wants.