Please help with severe bloating.

[dac122]

51 years old male with history of GI problems.

I have had GI issues for a number of years on and off.  Recently I have been experiencing severe bloating for 6 months now.  The doctor has thrown out a number of suggestions from slow digestion, to IBS, to sensitive stomach and constipation. I feel better for a short time at least when I burp, pass gas or have a BM.  I always feel like my BMs are incomplete.  I am due for a routine colonoscopy in a month.  My doc upped my Mirilax to 34g per day, and wants to wait until then to write a prescription.  Increased Mirilax does not seem to be helping a lot.  I am at a loss of what to try next.  Not sure I can wait another month.  

Things tried:
• HIDA scan 2003, nothing abnormal
• Upper Endoscopy 2011, nothing abnormal
• Two colonoscopies 2014, 2011, polyps found, nothing abnormal
• TSH and Free Thyroid checked 2011, 2012, results in range
• Bacterial Overgrowth Breath Test 2018 negative
• Magnesium, stool softener and Mirilax help somewhat
• Dexilant PPI seems to settle stomach
• Food journaling and FODMAP diet shows no particular food intolerances