Hi my 15 year old son suddenly started having gagging fits, and a clear fluid would come up. One time he said it tasted salty. Randomly he said his neck around his throat would start to tighten therefore causing him to gag. As soon as he's done eating it starts, we will still be sitting at the table and hell run to bathroom. It doesnt happen when he sleeps at night. His stomache does not hurt, hes not nauseous, he has no other complaints. No heartburn or burning in esophagus?