My DD2 had colic and silent reflux. She was on zantac for over 18 months as it took that long for it to go away. We also used to lay her over our knees and play the bongos on her back. This seemed to help bring up the last little bubbles of air in her tummy, also rub around her tailbone (with some oil) for a few minutes a few times a day. This stimulates the bowels and also helps relieve their little tummies as well (old clinic sister suggested this to me and it works) by making them break wind (how polite lol)

You are definitely not alone in having a DD with this. It nearly drove us mad until she was diagnosed.