This is EXACTLY what is happening to me. I feel like I can't take a deep breath and it's only relieved when I force a yawn (which is successful about 1/15 tries). When it works, its an amazing feeling, and its gone within 15 seconds. This started happening to me a few days ago. I have NEVER had this problem. I'm 25 years old. Not a smoker, not on birth control, work/stress a lot (but nothing in particular has been stressful over the last few days). Not over weight, though I don't exercise as much as I should/used to (because of work). I'm female. HELP!!!!!! I went to a walk-in clinic last night and she put me up to a respiration machine (I guess the same as asthma medicine). I felt ok last night, but not completely. Not allergic to anything. Been freaking out since I've been researching this - it sounds like there is no cure?????? Just had a successful yawn, so amazing.