I am sorry to hear Toltec's breathing is worrying to you, and I am sorry you did not get help from an expert before now. I just came online and saw your question. My name is Rebecca. I am a veterinarian and will do my best to help.
When the labored breathing occurs, is his mouth open to breathe? Or can he breathe with his mouth closed?
When this happens, check his gums to see if they are a normal bright pink color or if they seem pale. If his gums are pink, he is getting enough oxygen into his lungs.
When this happens, does he make loud noises at all? If he does, are the loud noises when he inhales, or when he exhales?
Sorry for all the questions, but I can't see and examine him! This could be a minor problem, such as "reverse sneezing" (gums would be pink, and he would make noise with inhalation) or it could be something more serious like fluid in his lungs, heart disease, or "lar par" (laryngeal paralysis). The more information I have, the more I can help. If his gums are pale then he is not getting enough air and oxygen into his lungs, and this could be serious. If he has lar par, there is medication that might help him breathe better and not have these episodes.