Your problems are hairfall, excessive yawning, flaccid muscles and burning sensation of feet off and on. These arises most commonly due to nutritional deficiency or iron deficiency or thyroid disorder. Other than these minor issues,there are also some other major possible medical conditions which needs to be evaluated first than treated under consultant physician. The major issues may be multiple sclerosis, neurological deficit, cardiac disease, aortic dissection or sleep disorder. Maintain proper diet. Excessive yawning is a serious medical symptom which needs careful clinical examination, laboraty evaluation and treatment accordingly.