Yes, I think pigs can get twisted guts - but if this was her problem I don't think she's be very happy at all !
More likely just a bit of wind, especially if she's peeing, pooing and eating normally. Has she had lots of cabbage or sprouts (the same things that give us wind will give pigs wind) Pigs should be wormed every 6 months, preferably with something that treats internal and external parasites - don't know if your herbal one would work for the external ones. Would be worth checking out, but it's not likely to be related to the bloated belly.
Keep an eye on her and if anything changes or she becomes distressed come back and tell us.
HTH
Karen