Thanks for writing your query.
Pain in left lower side of chest can be due to different causes.
You should have following investigations :-
1. Complete Blood Count(CBC).
2. Absolute Eosinophil
3. Chest X-Ray PA view.
You can take antacid
20 mg along with Domperidone
Follow some precautions like :-
1. Avoid spicy/oily foods.
2. Donot miss a meal.
3. Drink lots of pure water atleast 8-10 glasses in a day.
You should also get yourself clinically examined.
I hope this is helpful to you.