Hello,
Acid coming up your month could be a gastro esophageal reflux related problem, this mostly requires an upper GI endoscopy for evaluation and started on treatment depending upon the endoscopy findings, and mucous in stools is a protective process, u need to see if after eating any specific food does this occur, sometimes few gastritis like problems can also cause this, hence getting evaluated with an upper G I endoscopy n treating the cause would be a better option but seeing your private physcian is better because pain in the abdomen should be examined personally and evaluated, burning sensation plus blood while defecating can be sometimes be because any acidic food consumption or infective changes in your bowels, it should be examined and local applicant gels/ creams can be given depending on the examination findings.