Shortness of Breath (SOB) and Excessive Yawning

I'm a 51 yr old male and for the past 3 months or so, I have been experiencing SOB and frequent yawning.  It seems to come and go without warning.  When in full episode, yawning cycles about every 2 - 2 1/2 minutes.  Unlike others I read about, exercing doesn't seem to affect my symptoms much.  I work at home behind a computer 10-12 hours per day.  Have also underwent a CT scan and a cardio stress test and got a clean bill of health.  Only meds I'm on is Zocor for Cholesterol control and a regimented daily Asprin dose.  At 15 lbs overweight, I've never been sick a day in my life.  My job as CEO of a small business telecom company, stress is nominal.  Not sure what to do.