infant gas issues

Please help! I am looking for any help I can find with regards to infant gas problems. My formula fed, almost-4-month old has had gas since day one. We have tried it all - gas drops, chamomile tea, holding him upright when feeding, holding him upright for 20 minutes after feeding, pumping his legs, even the wonderful Gripe Water - nothing works. He struggles night and day and even his pediatrician doesn't have an answer. It is not getting better as he gets older. We even switched his formula to soy. Has anyone found a tried and true method to help? Perhaps goat's milk? Thanks!