Did I have have too much fiber?

Hi, Im having a bit of a problem. Today I went from having almost no fibre in my diet to eating several bran muffins and whole grains in 1 day. I went for a 7 mile run and I am now having immense pains in my lower abdominal and its been going on for about two hours. Is this constipation. Could it be something else? How long can I expect this to go on for. Its a mix between getting kicked in the groin and being punched while unflexed :(