hi i had gone through your query and understand your concerns. i would come up with two most possibilities to fit your condition .these include
1.first possibility is,gas trouble (or APD ACID PEPSIC  
DYSPEPSIA ).
-irregular dietary habits,
-modern lifestyles (drinking,
smoking,etc),
-EXCESSIVE USE OF PAIN KILLERS,ANTIBIOTICS,
STEROIDS for even minor complaints, 
-CURRY,HURRY, and  NIGHT WATCHING,
-SUPPRESSED STRONG EMOTIONS  are the main causative factors
2.second possibility is,RENAL STONES;
ultrasound scanning for KUB may confirm the diagnosis.
I hope this is helpful for you,take care,
 thank you