Thanks for writing your query.
Chronic alcohol intake usually damages the mucosal lining of the stomach resulting in gastritis
Pain felt by you is most probably due to this.
It is advisable to gradually decrease your quantity of alcohol intake and then stop it after some time.
Also avoid oily and spicy foods , donot miss a meal and avoid stress.
Taking antacid like Ranitidine
150 mg twice a day or Omeprazole
20 mg once a day will help you. Antacid gel will be more beneficial as it forms a protective coating over the damaged mucosa. Take medicines after getting yourself examined by your doctor.
If the problem persists, get an Endoscopy
done and consult a Gastroenterologist
I hope this is helpful to you.