Tighness Pain nearand chest sternum.

I am feeling a lot chest pain near behind sternum its tightness like indigestion feeling.passing gas gives me comfort.and a exactly opposite site i am getting the back pain.nl shoulder or arm pain at all.i have a b12 defeciency and i am taking supplements too.but even whatever i eat the chest pain occuring.3 montths back attacked with chickenpox,and some cough .now cured but still i need to clear throat.normal chest ct scan and sinus.i am taking pantropazole tablet. From 2 months.if i take it would be good.if i stop again the problem coming.2 months back upper endoscopy all heart related tests done like 2d echo doppler stress test ecg.everything is normal except vitmin d and b12 defeciency.from two months i am taking supplements.But this gas problem persists.upper abdominal and lower chest strenum pain and back pain exactly to opposite of chest.please advise me.no heart burn.