What shall I do for acidity and stomach burn?

Hi doctor,

I am a 23-year-old male. I have an issue with my stomach for the last few months. I had Ponstan Forte (a painkiller) for my headache for almost two years. I used to take the tablet in empty stomach usually and rarely after food. About eight months ago, I had a stomach burn near my stomach mouth, a point at the right side under the ribs. That time I used two or three Omeprazole tablets and it became all good. Then after one month, it happened again. I had acidity and stomach burn because I used to stay empty stomach. Along with this, When I sleep I got much saliva in mouth and woke up many times at night to wash it. When I visited a doctor, he prescribed me Omeprazole once daily and Ganaton three times a day for a month. Then everything remained fine for two weeks. Then I took spicy hot soup once in empty stomach and then again the problem started. Then I remained untreated for three months. When I press my rib cage at right side, I feel sore and slight pain. I do not have any symptoms now. Whenever I skip food, I feel acidity. What should I do?