I don't think anyone outside of a vet will be able to help you here.
As far as snakes go, the esophagus is fairly long. If there is a growth there or an obstruction, a vet would need to diagnose it.
Snakes primarily use body movement to move prey items down the esophagus rather than the peristaltic muscular movement of the esophagus itself. In other words, if she isn't having any issues with mobility, the vet will need to examine her for a potential growth or blockage.