I Have Had Trouble Having A Bowel Movement For More

I have had trouble having a bowel movement for more than a month now and have this on and off again pain above my naval and under right ribcage. I noticed it after a weekend of heavy drinking and it burns when I drink alcohol. My doctor told me it was gastritis and have been taking Prilosec and a anti-inflammatory medicine. I haven't been nauseas, but today I am. I worried it might be something more serious. I haven't thrown up and no blood in stool. Is this common with Gastritis?