Gastritis pain. Resolve the infection?

Hi, I am suffering due to pain below the left side ribs. It has some swelling on ot. I consulted the local doctor in village. He said the issue seems related to Gastritis and has swelling on the stomach (Jathar). This third time I am facing this issue/ symptoms. There is no back pain in that area. But I usually suffers from acidity and feels heavy throat. The doctor has prescribed some anatacids liquid/ tablets and antibiotic which contained Ofloxacin and Ornidazaole Along with it he advised no to eat spicy, oily and non-Veg food during course. But I remembered that I have some allergies and sensitive to the Ofloxacin and Ornidazaole drugs. Might be for Ornidazaole. Because it had caused me symptoms like balanitis, itching, which had required almost done 2 weeks to resolve. What could be exact cause for this pain/ swelling? Can you please suggest me some alternative good medicine/antibiotic to resolve the infection? Thanks.