Yawning is a somewhat understood phenomena that does not seem to have too much to do with your lungs, and more to do with other factors. Most people don't yawn in order to get more oxygen into their lungs, as there are much more efficient ways to do this. There was a study recently that suggested that the temperature of the brain has something to do with the stimulus to yawn, although this is unclear. It is also unclear why yawns seem to spread so easily from one person to another (sometimes people say that yawns are contagious, for example). In short, there is much that we do not understand about yawning. What we do know, however, is that it could be a sign that you are sleepy. Drowsiness can come from many things, some of which include simple problems such as poor sleep hygiene. Other problems can be more serious, such as sleep apnea
. Speaking to your doctor
about your symptoms is always an excellent step towards making the correct diagnosis, as he or she will be able to ask the appropriate follow up questions and get you started towards feeling better. Please speak to your doctor.