Gray showing through porcelain crown. Is there anything the dentist can do? Is it something I have to pay for again? (Photo)

You need a root canal. The film shows deep decay extending into the distal pulp horn of your pulp chamber (the cavity is in the area of your tooth containing your nerve and blood supply.) Your reporting of your symptoms follows classic progress of decay though the tissues of the tooth. Pain on...

This sounds to me exactly like what Dr. Maddahi proposed when he said "incomplete root canal' First of all, your root did not grow into your sinus. If your root was growing still (which its not) it would just slowly push your sinus membrane. Even if it did puncture the sinus (which it...

This is likely the root. Sounds like the post broke off with the crown attached to it. Make an appointment with a local dentist to see what your best treatment options are.