Quaker Breakfast Cookies Why Is It When I Eat Foods That Have Extra Fiber In Them I Get A Stomahe Ache ?

Why is it when I eat foods that have extra fiber in them I get a stomahe ache ? - quaker breakfast cookies

I ate the bread with fiber and adding a very bad stomach ache long.
And I ate Quaker Breakfast Cookies with added fiber and had received abdominal pain.

I asked my friend and told me I had the same problem when he ate the same breakfast things.