Bouncy chair cheaply ones can be better as they bounce a little when DC wriggles legs - mine was the most basic of the ones with a vibrate and music function.
Sling or carrier to keep upright.
Once old enough, if still suffering, a jumperoo - DS loved it and it saved my sanity.
Early weaning is a myth and does not help, most babies just grow out of it at that age anyway (I won't lie though, it can last some, like my DS, well into toddlerhood). In fact weaning can cause more pain as it makes things more acidic.
If a combination of gaviscon (a feed thickener) and ranitidine (an acid reducer) does not help a lot then make sure allergies are explored.
Do not use gaviscon in antireflux milk as it will double dose on feed thickeners (the gaviscon packet does warn not to use with other feed thickeners but lots of people don't realise that's in antireflux milks).
My DS had a breathing problem that was exasperated by being on his back and a little by being on his side, so had to tummy sleep because of that. Tummy sleeping vastly helped and I think I would be very tempted to do it with my next if they have reflux.