We took Jimmy to a cranial massage therapist for his reflux/wind issues when he was a couple of months old - wish I'd taken him sooner. The treatment didn't completely resolve his reflux (that disappeared once he started on solids) but it definitely got rid of his wind issues. The therapist said it felt like he had a huge balloon inside him, which she managed to 'release' - don't know how exactly but I heard lots of gurgles etc lol. After that he would burp really easily IYKWIM...no more groaning, moaning and pulling legs up ... no more pain.

Different burping techniques can help too. Try starting by sitting upright first and rubbing his back gently, then lift him right up so his legs can stretch out, then lay over your shoulder and pat gently but firmly - leaving the palm of your hand on one side of his back and patting with your fingers held together, from about halfway up his back up to his shoulders and repeat. Sorry, don't know if that makes sense!

ETA: Here is a link to a video showing part of this technique in action (very briefly!) - it's a 12 min documentary but start watching at 9 minutes for the burping technique.