Talk to Psychiatry on Digestive Issues For Past Almost 9 Years. Excessive Trapped Gas, Acidity And Constipation Issues

For the last 9 years approximately I have been undergoing digestive issues, initially it was just frequent constipation but over time it went on worsening and turned into acidity and excessive trapped gas. Now every time I remain stuffed with trapped gas and develop acidity promptly followed by constipation and sometimes constipation but with normal stool because I try very hard efforts to pass the stool. Consulted one of the Gastroenterologists who observed and guessed that I may have an IBS problem and secondly I need to go for colonoscopy because vitamin b-12 was very short in blood tests. please suggest should I go for a colonoscopy? or what should I do to cope with this. I also take anti-allergy daily for flu otherwise I develop flu, nasal congestion, runny nose, and sneezing.