Agreed that you should try to see a pediatric GI ASAP. But while you are waiting for the appointment, ask your pediatrician if it would make sense to try a PPI, which is likely to be the first recommendation from the GI. Also, if your child will need an endoscopy, the GI may want your child to have been on the PPI (such as prevacid) for at least 6 weeks. The GI may want to check for eosinophilic esophagitis, which requires an endoscopy to diagnose. The endoscopy can also look for reflux, etc.