Reccurent episodes of vomiting in my 8 year old sister since 4 months.. All her investigation reports are normal like blood parameters head ct scan abdomen ct scan and endoscopy. Eeg is also normal... all the reports are normal. But still she vomits continuosly after every 15 days. Doctor prescribed pan 20 but as soon as she stops taking pan 20 she starts vomiting. Immediately after vomiting she complains of headache. It's been 4 months since this is occurring. What might be the reason even though all the reports are normal