Gulping- Can Anyone Help??

So, we have been dealing on and off with a new issue.  About a month ago I posted how grateful I was (and still am) that we got through a night where Murray seemed to struggle with a piece of Milk bone in his throat.  Well, that same choking type reaction happened again a couple times this past week, and it wasn't related to having just eaten.  It's made me a bit nervous and I have spoken to my vet and done tons of research.  I believe it's an ailment (I call it an ailment because I'm not sure what else to call it) people have dubbed "gulping".  It doesn't involve gulping food or water, but instead it's a rapid swallowing and gulping of air.  As it gets underway, it turns into gulping grass outside.  It seems to be relieved through the grass ingestion, calming him down through gently petting and many times a loud burp.  In all my research, I have learned many people have this issue with their dogs, and it's gone undiagnosed.  The three main thoughts about a cause are that it could be a seizure type behavior (this one I least expect personally, but who knows!?), an allergy to something (likely a food item or ingredient), a reaction to stress and anxiety, or some form of acid reflux.  Murray is definitely an allergy prone dog.  He always has ongoing skin allergies we work around, he's allergic to sulfur in shampoos and medications and now perhaps something else unknown.  Our vet also placed him on an acid reducer and other medications for a short time last year, after a bout with sickness, and an x-ray showed inflammation in his stomach.  He recovered well, but we have always suspected there is an issue with acid since he tends to vomit bile when his stomach is completely empty....  And, Murray IS a sensitive dog who can stress easily.  So, I have a triple threat!  Oiy Vey, he sounds like a hott mess!  LOL  My vet definitely thinks this gulping is digestion related based on the grass eating.  They have asked me to record the gulping when it happens...which is sure to show me being a nervous wreck instead of anything of value!  So far, thankfully we have not had another extended episode, so no recordings yet, just quick bouts.  I am discouraged reading online how none of the dogs with this same issue have been able to be diagnosed by a vet, so I assume it may be no different with my vet :(  I will link a couple videos I found online of dogs doing this gulping action.  While the dogs in the videos looks fairly calm, Murray, and many others I read about, panic a bit during these episodes.  I am uncertain what is causing the panic, but it certainly then panics me.  We have been using Pepcid to help with acid this week, and I have taken him off of the veggies I had been feeding as a mix into his dry food the past month.  My thoughts were that the veggies cause a lot of gas, and along with the gulping, I could hear his stomach churning last night, so veggies are out and a good grain free wet food is in.  We have also started him on some plain, fat free yogurt for some "good" bacteria.  I would LOVE any words of wisdom from anyone out there that may know something about this.  Also, I have eliminated "tracheal collapse" as a possibility right now, as he really does not exhibit any other symptoms for that.