9 month old burps FORTY times daily

I have a nine month old who was diagnosed with reflux at 3 months. He has been on Zantac and Prevacid, which both stopped working. He is no longer on medication because they were not making a difference. We have also seen a GI and chiropractor and no one can help us! He doesn’t vomit any more, but he has to burp constantly. I will keep him up 2 to 3 hours after his bottle in order to burp him before laying him down to nap and 45 mins after sleeping, he wakes up screaming and has to burp again. He burps at least ten times with every bottle he drinks. The nights aren’t so bad, but the days are terrible. he is so grouchy and over tired. I have also tried letting him cry it out, I’ve tried sleeping wedges, and I have recently weaned him off of the pacifier because I thought that might be contributing to his burping – it seems to have helped some, but not enough. any ideas of what is wrong or what I can do????