There are some tips about running eating habits:
1. You should eat 2-3 hours before running.
2. Eat at least 30 minutes after running.
3. Eat light food before running.
4. Sometimes it happens, that you can't eat 2 or 3 hours before running. You are going home you and haven't eaten for 5 hours, but you have to run when you are back home. Maybe it takes 30 minutes to run, when 15 minutes for a shower and after that you will feel very very hungry and will want to eat a lot of food. So if you don't want this to happen, have some fruits with you every time. Just eat an apple or a banana when going home. You will forget about hunger and it won't make you feel bad when running.
5. If you are running in the morning it's really god to give some work for your stomach before running. It's good to drink a cup of tea or eat some fruits. Maybe not all big apple, but just a half of it. It really makes you feel stronger when running :)
6. Drink water with salt. It helps to get minerals back.
I really hope that these tips will help you to feel better when running and you won't feel any pains in your stomach.