I have a boxer that was a year old in January. Friday morning he started throwing up his food then white foam. He has not lost his appetite however he is having trouble swallowing. So he will try to eat but then it comes back up. When he swallows, he swallows hard. When he's about to throw up, he starts making this noise almost as if trying to work up a lugie... not a cough or a choking noise. I took him to the vet and they gave me no actual diagnosis, but gave me pills to stop him from throwing up. They took an x-ray of his stomach thinking maybe he had eaten something that he wasn't supposed to. (which he has a habit of such as socks, underwear, hair ties) X-ray was fine and no temp. So even after trip to vet, he's still doing the same things. He is sleeping more than usual also... any ideas of what's going on?

I think a call to your vet is in order. Let them know that it has not improved and that he is sleeping more than usual. There is something going on that needs to be fixed. Have you tried moist food for the time being to see if that will help until he gets better? Just thinking it would be easier for him to swallow then dry food.
Susan

My first thought was megaesophagus, the symptoms sounds very similar to what you are describing.
It is basically where the muscles inside the throat are not working properly and the dog has trouble or an inability to swallow resulting in coughing and/or vomiting.

Canine Megaesophagus, Aspiration Pneumonia & Myasthenia Gravis

Megaesophagus produces a quiet, non retching vomit. It is a distention of the lower esophagus, near the stomach, which becomes more a pouch than tube and collects food rather than passing it into the stomach.

You mentioned a noise like he is trying to work something out of his pharyngeal area, and white foamy vomitus. This white foam is thick saliva mixed with air, and it is quite 'clingy' to the back of the throat. Being a boxer, he has a built in propensity to nasal/pharyngeal congestion, with his shortened face.
I would wonder about a about of tonsillitis causing the throat congestion and difficulty swallowing, and a gagging on the thickened tonsils and saliva, producing the vomiting.

I, too, recommend a return to the vet's, plus a good look into his throat while the thermometer is up his rear, and possibly a course of antibiotics?

My first thought was a reverse sneeze which boxer and other stout snouted breeds are prone to. My female does the same thing, but she has a heart murmur. I assume your vet had a good listen to the heart? Even the lowest grade murmur can cause gagging and retching. My dog will do this reverse sneeze after she is done eating or after she gets up from a nap. One thing that I stopped using was those powders on the carpets to get out pet odor. Also if I use scented candles or those glade plug ins, she seems to have more attacks.

I'm going to echo everyone else here and suggest a return trip or a different vet all together.

I didn't think of it till later, but don't discount the possibility that your dog may have poked the back of his throat by running into something while carrying a stick, or even just bumping the ground while carrying a it. Doesn't have to be a significant, easily seen injury to be a bother to the dog. Probably why it is often overlooked on exam.

Well there you go, 4 different interpretations by 3 different people.
Goes to show how hard it is to figure out what is wrong just by the symptoms, hopefully your vet will be able to pinpoint exactly what is wrong during a physical exam.