4 year old complaining of upset stomach for the past 2 to 3 months. she sometimes throws up and gets a fast heart rate.also feels a ball in her throat?

Need more info: When there is a long standing history like you mention, including the other symptoms along with upset stomach, a full history and evaluation would be needed. I would suggest starting with your pediatrician for a complete physical and evaluation. It is important to note how many times per day she complains of pain. Before or after meals? location of pain? other symptoms?