hi i had gone through your query and understand your concerns. i would come up with the possibility of FLATULENT DYSPEPISA or ACID PEPTIC DYSPEPSIA
may be the cause for your sufferings.
-eating spicy, fatty and junk food.
-lying down soon after eating
-taking pain killers
-lack of physical exercises
-drinking alcohol and smoking
are some possible causes.
I hope this is helpful for you, thank you