I would start you on antacid like tums or proton pump
inhibitors (PPI) like Omeprazole
(prilosec). Other alternatives warm glass of water / milk. If you don't feel better, I would urge you to visit the ER for evaluation and IV injections. I will urge you to use antacid/PPI for 2 weeks if you feel better.
Besides that you can use benefiber 2 tsp twice a day instead of magnesium citrate
. These are over the counter medication
Along with medication you have to change diet habits to avoid constipation and burning sensation in stomach. The following suggestions might help:
Drink plenty of water.
Eat fiber contains food which helpful for your digestion and prevents constipation.
Eat healthy vegetables and fruits.
Avoid smoking if you does.Restrict alcohol intake.
Restrict hot beverages like tea and coffee.
Avoid oily,spicy,fast,junk food.
Avoid heavy or fatty meals which causes constipation
Hope I have answered your query.
If you have any queries I will be happy to help you.