Look im not trying to scare you but...
When i was in middle school my tummy used to hurt and i feel tightness without any reasons, and i had red spots on my face ans scalp, when i went to the doctor he said the skin is treatable but the pain isn't, he didn't want to hook me up with pills so he said i just need to relax because stress it's what causing it.
But when your family is poor and your dad beated you up most of your childhood, and when in you either win a fight or get beaten up in school and you have no friends, you can't really distress.
I live with constant pain and tightness in my tummy, it goes off when i lit a cigarette, smoke a joint, or work out, but most of the time it hurt, and im just gonna live with it for the end of my days.
I hope you're not getting the same problem as me.