You might be having something like IBS.
Avoid outside food and bakery stuff.
Avoid milk at bedtime.
Have food at regular intervals. Have early dinner.
Avoid oily foods, chocolates especially at night.
Cap. Sompraz IT 1-0-0(1/2 hour before breakfast) for 10 days might be of help.
Take Tab. Rifagut 550 1-0-1 after food for 2-3 weeks.
Cap Procraft 1-0-0 after food. For 3-4 weeks
Next Steps
colonoscopy and biopsy might give additional information