Please help with the issue

Patient: My question is i had gastritis twice, once in 2007 and now in 2011, in both periods of time i did doctor prescribed treatment and felt good, but now after one month of treatment, i feel better, however every day sometimes i have lower back pain, from mild to moderate, also abdominal discomfort, i feel food digestion process all the way through and it’s discomforting, also mostly have a lot of saliva and passing a lot of gas, it feels like a relief for a gas, especially at night going to bed, have gases and feel relief. Have no pains at night, only after eating, also sometimes when hungry too much, i feel episodic throat pain. i had a large meal. ate a lot, didnt drink alcohol and no cakes, sweets. and then same started lower back pain and abdominal discomfort all together, passing gas difficult it takes time to digest and then it all goes away, please tell me , what is wrong? age 23, male