Most often the occasional abdominal pain
after eating or drinking
occurs due to contraction in the intestines called "Peristalsis".
This happens in some more often than others. Cold
tend to cause more contractions than hot or warm drinks.
Try to chew your food slowly and take the drink after you are
done eating. Drinking during the middle of the meal sometimes
you swallow more air which can add to the bloating
I am glad that you are trying to get enough fiber in your diet by
eating more vegetables and fruits. Keep that up.
If your bowel movements are regular then there is less chance for
gas getting trapped in the intestine and giving you pain.
Wish you good health.