Gagging & vomiting with solids

Hi guys, our Flynn has reflux & a dairy allergy and has been on solids for a couple of months now. He will often gag and vomit on the solids and I think its getting worse. The Last time we were at the dr and mentioned it to her (was happening to often then) she mentioned that it can sometimes happen with reflux babies and if it continues we'd have to take him to a spec up at the hospital. I didn't really ask much as I was keen to get home since he'd just had his shots. Does anyone know anything about what it could be or been through it? I'm hoping I'll get into see her this week but with it being a long holiday they always seem hard to get into for the few days after.