The problem is NOT IN YOUR EAR CANAL! One of your eustachian tubes which connects your throat to the middle ear(area behind the eardrum) is malfunctioning. This is causing a pressure difference on the two sides of the eardrum, causing your eardrum to be pulled inwards causing the crackling sound when you yawn!
Next Steps
Please drop in to my clinic where I will examine you thoroughly and prescribe you medicines through nose and mouth to remedy the same.
Health Tips
Drink plenty of hot fluids in the meanwhile.