My child had an episode the other night of sitting upright and burping and burning acidic like sick came up in the throat. Poor child was really scared and it hurt the throat, because it burnt. I gave some milk and was fine. Happened again today and again frightened the child, i asked what eaten and said at school they gave them a lot of sweets as it was their last day of term. What causes this, child is very thin, but has a reputation of eating rubbish sometimes too.