Lower abdominal/stomach ache/pain?

ok i have weird stomach aches in the lower part of my abdominal. during December i was on a diet, low carb/no carb diet. i was going for about 2 weeks. then my cousins came from florida and i continued my diet but then one day i cheated. that night i cheated i had the worst stomach ache i've ever felt. it was sharp pains, i was on the john, and my stomach was killing me, i was breathing very deeply like i could'nt breath. then i went #2 and my stomach felt like it was in HEAVEN!!! literally, it felt so good lol. anyways i had one stomach ache after that, but it wasnt that bad it was a regular one from to much mixing of foods. during the months between december and now, i've been on a strict diet, and for this pass week, my stomach hurt everyday once a day for like 5 minutes and then i would go to the bathroom and feel better. then just yesterday, i woke up, and was twisting and turning, at around 8 o'clock in morning i woke up to go to the bathroom and had the sharpest pains, i was yet again breathing deeply, i didnt end up going, so i took some pepto and went to bed, woke up 15 min later, and finally went, my stomach was alot better but then i got that feeling of emptiness so i went to bed and slept for another four hours. i then work up and felt so much more better just felt very hungry. then just today i went to the bathroom once alot then a little twice after i had an omelette. but the pain is in my lower abdominal to middle abdominal like in the stomach though, its not like the pancreas or gall bladder so i dont think i have gall stones or pancreatitis. so is it just cause of my diet, my diet is low carbs and 5- 6 meals a day but lower quantity. im 14 years old, 245 lbs 6'-6'1'', i know im a little big so thats why im on a diet, but i have most muscle only my stomach has alot of fat my legs arms and chest are pretty built. so what could the stomach aches be? thanks