Stomach pains when road running

Question
i am male 33yrs  - 6ft 4- weigh 13 stone - get stomach pain on my right side abdomen after about 30 mins of road running - this goes away when i walk it off  after 3 mins - then gradually comes back after time when i start up again. this is fustrating on my rythym and hampers long distance running - the big thing is that i can easily do 1hr on the treadmill and not experience this pain.
i was not long ago assesed by my physio on a left knee problem  - that was due to my  left leg  being 1cm longer than my right leg. (not sure if this may have something to do with it -

i do not experience this in doing weights/golf/rugby

i do 30 sit ups a week

Please help

Chris  

Answer
Hi Chris
It is not your leg.Running puts a lot of stress on the abs and if there weak those symptons can surface.When you run out side your stride will open up quite a bit more than treadmill.This will stretch the abs a little farther.This is what i think is happening.Also ab problems do effect people who are just starting.I don't know how long you have been running.I think you should do 30 sit ups a day.

All the very best

John