I have a sharp piercing pain in my left ear that started this morning and has been happening intermittently (at least every half hour or even less) all day. I have no fever or other sickness symptoms right now. I also went to the dentist last Thursday for a routine cleaning but nothing else. I have no sore throat nor do I have tonsils. I had half my thyroid removed many years ago but have never taken medication and regular checks of it have all been good. What might this be?