Hi Ben
Does sound like wind, the typical shoulder pain and bloating. Have you tried any wind preps? Peppermint tea, gripe water, chewable deflatine will help. Keeping up and mobile, do some wind mills with your arms to release any wind in the showers. Hot water bottle on your shoulders.. lying in your L side can release the pressure on the nerves so may offer some relief. The intake of fluids should get easier as the wind releases and the post op swelling settles around your band site.
Suck some ice cubes. Make sure fluids are thin, use a teaspoon and 20 seconds between whilst the swelling is still very much apparent.
If things don’t settle speak with your provider… it does get easier just keep your sips slow and continuous to hit a good level of hydration and nutrition xx