my chihuahua does that too..i have gotten him checked out by a vet the vet told me it is common in small dogs...and yes it is freaky cause mine does that with a seizure type jerk with it its like he is snorting threw his nose and does sound like he is choking..i even asked the vet if its possible for him to have asthma he told me not likely and its common....sorry i dont have a clear answer for that im still trying to investigate myself cause theres gotta be something going on there......
He could have something stuck in his throat, yes. Best thing is to take him to be checked by the vet.