stomach ache after eating a little( a bowl of cereals or an orange) ? can

[Bob]

somebody help me? yesterday i didn't have time to eat home, and had only a coffee and a couple of cigarettes. when i got home i tried to eat an orange and was in pain for about an hour. this morning i ate a bowl of cereals and i was in pain for an hour. i don't eat regular but i eat healthy and i don't get stomach aches from eating heavy meals. and it can’t be from the smoking because my lungs are fine( I get them checked twice a year.)