All drugs have side effects, and all drugs accumulate and add to the toxicity that your body has to deal with. Building health is about helping your body clean house. You will not build health by drugging your symptom of fatigue.
You don't necessarily need to feel anxious to experience this symptom. However, if you don't spend time in quiet stillness, practicing relaxation, you may store enough tension in your muscles that it inhibits deep breathing. The quality of your breath will determine the quality of your life (energy level) and the length of your life. It is a proven fact.
Come on over to Heart Failure Solutions and check out the Breath Building category, you'll find great resources for building your breath, and there by your energy level. Don't put it off another day, the answer to your health issue is not a pill, an X-ray, or a test. Be well, many blessings.
It is conceivable that this is an unusual symptom of chronic Lyme Disease or, possibly but even less likely, a side effect of adderall. It could also be a symptom of the Chronic Fatigue Syndrome. Most commonly, however, and despite your assertion, the need to yawn or take a deep breath or the inability to do so is on the basis of anxiety. Nevertheless, it would be important to determine if there is any measurable physiologic abnormality for your symptom and to do this, you should have a chest X-ray and pulmonary function testing, with inspiratory and expiratory flow-volume loops.
Good luck