I started to eat nutritious foods because of my abdominal pain

Oh my! If this pain persists, you really should go the doctor to check it out. Not to say you have any kind of illness, but IF you did, it's better to find out now and do something about it rather than delaying your healing process or worsening your condition. Eating too many of a certain kind of vegetable and fruit can cause diarrhea too - so be careful.

If you have stomach pain, you can diagnose what your issue probably is from reading articles on line. If it was just your stomach, odd are you have too much stomach acid so staying away from fatty foods or acidic food would make you feel better. If its lower abdominal pain, there is a chance it is constipation and increasing water intake, fiber, eating yogurt & more fruits and vegetables may help.