HELP? stomach problems?

hi im 18 i dont eat breakfast, i eat late at night, i dont eat nothing till like 10:00 or 9:00. I eat junk food alot, i eat whole wheat bread alot but lately i've ate white bread alot, and it been giving me stomaxch problems i dont eat good at all like i dont have a meal course at all, i sleep late due to computer, im a virgin, on Nov i bought meatball marinara with italian bread footlong in subway, and slept after that and woke up with left side pain in stomach and it stop and came back this year like jan 3 or 4 . i dont drink water like i should only minute maid, those corn syrup drinks like Ssips, which is bad for me, one time i bought a plate of cooked porked chicken and drank a gl of C&C g soda and next day my stomach was like war gas GAS GAS GAS ALL OVER INTESTINES, it was so loud like whoa, my mom said eat healthy eat vegetables i do but not anymore, i know it bad today i bought pomegranate juice pure in health food store, and im a female my period finished on saturday. and like 2 days ago my left side hurts with gas and i hear it radiated to the right side upper right side, and like the side hurts it never happen before so my mom bought a colon cleanse and liver cleanse and i took it today and yesterday and well t takes time to go into effect, my back hurts also it like a bacteria infection, i only ate yogurt today. i need like a nutrionists who can guide me in eating good food, likw what should i buy? what should i eat for breakfast, lunch, and dinner please tell me, my mom has stomach problems it runs in the family and it's bothering me like burning sensation, gy, bloated, and i never had that problem it not so severe i give it an 8 , a friend whose a herbal practioner said my alkaline balance is i guess way to high get it back it normal size by eating right but how should i start? like the left pain in my stomach went to the right side with back pain and like why??? what should i do?