Welcome blowe 46!
Benedryl will act on the cough because it helps to dry the mucous; the mucous can be caused by sinus drainage, throat irritation, some sort of virus, etc., so that does make sense. I can't explain the sharp pain though and, in my mind, pain is God's way of saying somethings wrong here!. I think you should get that checked out.
Do you have an ENT or a good family Dr? That would seem like a good place to start? Do you have a history of reflux?, if so, you may want to see your Gastroenterologist. Make sure you let whichever doctor you see know that you're having heartburn symptoms as well.