Every time i yawn, i get a sharp pain in my ear and it's so sore, what is this, what to do?

TMD: When you yawn, you open your mouth wide and the mandible (lower jaw) comes forward and may irritate the jaw joint. It is not pain in the ear but more likely pain in the temporo-mandibular joint. See your dentist for confirmation. Remember, if you have an earache and your hearing has not changed, it is virtually never the ear that is causing the pain.