Mine started doing it around 3/4 months and it turned out to be silent reflux and milk and soya protein intolerance. Gaviscon never really helped, she was on ranitidine and omeprazole until she got better. Maybe get a second opinion? If you are breastfeeding, have you tried dairy free diet for a few weeks?
I don't know what has happened to my little one. A previously happy baby is now often crying, grunting, straining and arching his back often. I know we are Wonder weeking but its never been this bad before.
I thought the grunting and back arching could be reflux but now I am not sure as sometimes he will stop when put down flat and Gaviscon hasnthelped.
It's like my baby has morphed into someone else. I started feeding him 3 hourly rather than four today in case that makes a difference if it is tummy related.