Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
Since all your symptoms of pain in abdomen particularly after having meals, long time taken to pass motion, have to press on bowel may be due to
irritable bowel syndrome that is called as IBS.
All your relevant investigations of
endoscopy, blood reports, and
ultrasonography are normal except for low calcium also goes in favor of IBS (Irritable Bowel Syndrome).
The basic cause of IBS lies in psychological setup one has and taken over by stress and/or anxiety. Unless these are modified, reduced or stayed away from, one does not get relief with medications like Lesuride, Normacin or
Pantoprazole drug.
Also get the CT scan of abdomen,
colonoscopy and stool tests for three consecutive days. If a specific cause is found, then it will be treated accordingly. If all the reports are normal, then get a control over stress, anxiety and so on.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. T Chandrakant