Pain in abdomen. Due evacuation problem?

Getting sharp severe pains and tightness in abdomen(mostly upper part)and also chest(slightly towards left)pain also sometimes radiates towards back..During pain feel like either vomiting or belching.Had 5-6 such episodes since april(recent on 27.06.2019)TEndoscopy done on 18.05.19,Grade A esophagitis detected. Have a past history of Diag lap(done for SAIO)+appendectomy[doc said appendix was infected)(Aug 2017),Lap Nissen fundoplication(Oct 2018)for severe Grade D esophagitis,Subtotal Colectomy(March 2019)for colonic inertia.Now I have SRUS,Mucosal prolapse and rectoanal intussusception,due to which stools are getting stuck,causing great discomfort.My main question is what is my abdominal pain due to?Also feeling heavy near wrap(since last week) and passing foul smelling gas sometimes..Medication tried-Sucrafil,Gaviscon,Drotin(both DS and normal one),Simcon,cintapro,DycotiamOmez insta satchet..But no permanent relief?What is this pain due to?Is it due evacuation problem?Kindly help me