She's been complaining on and off for about a month. She says it hurts and feels hot.
Complains about it in the day and in middle of night (often as part of a dream where "a monster has put fire in her tummy").
Doesn't seem to be related to anything she's eaten, and she doesn't have any physical signs that she's in pain (no crying or holding her stomach). No vomiting or diarrhoea. She's 3.
What on earth could it be?