Thanks for the query to H.C.M. Forum.
After going through your query I reached a conclusion that you have hyper acidity or gastritis
, causes are as,
stress ( may be work related),
coffee or tea ( excessive),
As burps, chest pain
( lower left),
Pain in left shoulder,
2nd reason may be due to menopause
( if you are a female patient age 50 years).
In my opinion consult a physician and get his opinion.