Gagging, medical opinions please....?

Serious question. My doctor cannot figure it out. For the past several months whenever I get nervous, anxious, etc... I start gagging like I am going to throw up, but nothing ever comes out. I have the same problem after I eat a meal. It is now happening in the morning when I get up, in the evening when I leave to go home from work. I had an endoscopy, but that did not reveal anything. Anyone know what it could be. It basically feels like something is stuck in my throat and I get that gagging feeling to get whatever is in there out, but nothing is in my throat. It sounds horrible when it happens to and I cannot seem to control it. Any ideas?