Dear Zex...
My daughter, since very early in her life, has had the insatiable need to yawn, and it's not always the same thing that triggers it, until you look at the underlying cause.
She is also asthmetic, and much of her asthma is caused by stress, with a small amount of allergic reaction. Whenever she is stressed, if you go to say something to her, and she needs to yawn, she gets extremely upset, and this will trigger the need for her to reach for her inhaler, or struggle for breath if it is not handy to her.
While hypnotising her, as she relaxed, I noticed that she needed to have several pauses where she was able to yawn, as part of the process of relaxing. I do not think it is so much of a 'medical' condition now, as it might have originally been for her, but rather a learned behaviour - one that originally allowed her time to prepare herself for whatever was perceived to her (as a child) to be a stressful event - and admittedly she had enough of those in her life to probably really ingrain the habit. My solution with her, regards hypnosis, is to just work around it (we agreed on an idometre signal, where I would pause the induction and allow her the yawning time), as the other issues we are working on are currently more important than pushing resolution on this.
Not saying that the stress or the asthma are a factor for you, but have put this out there, so you and others might understand that this is NOT just one person's silly quirk, but a definite condition.
As to what to do about it - if any of the above rings true, or it leads you to think in other areas, then at least you get a clearer understanding, and perhaps then a way to decide if it's important enough or not to really try to change it.
Namaste
Unis 
