HI Alison - sorry to hear you're having such a rough time of it! Is there any chance you could consult a lactation consultatant again? Just to check the latch. If he's making a lot of noise, he may well be getting air in and this can upset his tummy and give him more gas. If he's sputtering, though, it could also mean that you have a strong letdown, which might also make it hard for him - although he'll get better at dealing with this as he gets older. You're right that if your nipples aren't sore, that the latch probably isn't terrible, but you might just need a refresher - there's nothing wrong with that!
As for the 5-10 min eating, that can be normal. At his age, many babies only need to eat for 5 or 10 min to get a full feed - they're much more efficient eaters than when they were small. And refusing one, but wanting the other also sometimes has to do with the milk flow. If they're used to a strong let down and the flow is slow, they get impatient. Switching sides sometimes seems easier for them. :wink: He'll also start getting better at doing the burps himself soon, so you won't have to pat him as long.
But if it were me, I'd check in with an lc or la leche league, as maggieruth suggested. It doesn't have to keep being so exhausting! Let me know if I can help more.