boyfriend has stomach aches and headaches everyday

Hello, this is in reguards to my boyfriend's symptoms. For about the past 2 weeks or so, he has been having stomach aches everyday. Sometimes they get really bad. He says he feels bloated sometimes, and he gets pretty gassy at times. His eating habits are alright (sometimes he goes some of the day without eating, then eats a large meal, but I've been trying to help him with that). He says he feels it right above his belly button.
Also, at least every other day he gets a headache, usually along with the stomach ache.
He's been trying to drink water and sprite to help his stomach.
I don't know if this is helpful information as well, but he's never really had (what I think to be normal--around once a day) normal bowel movements. I don't know if maybe it's just really bad gas, or if it's a serious condition. Like I said, it's been happening a lot lately.

Thank you for your time