Yes i have had 2 pups in my lifetime with megaesophagus
One is 5yrs old, Labradoodle, her owners have to feed her sitting in a special chair but she is doing well and now rarely throws up
This is after a couple of surgerys, this is not somthing they will outgrow,,and it takes a really special person to commit to a pup/dog with this problem
Depending on the severity it can be corrected
your vet can do a special test to see if that is what it is, if he is not equiped to do so i would go to another vet, Vet schools have the resources to diagnose and to treat,
another problem with this is that they can vomit and aspirate it causeing aspiration pnemonia which can be lifethreating