Hello there. Im sorry to hear you are experiencing such problems. I will try to help.
First and foremost i cannot make any definitive decisions or a definitive diagnosis without considering your full history and undertaking a full examination, but i will use to above information to try and advice you accordingly.
Pain around a tooth can either originate from the tooth itself or from the tissues surrounding the tooth.
1 -
If the pain originates from the tooth itself it is usually either due to decay which is encroaching onto the pulp (the
nerve chamber) or the filling is so deep that it is close to the nerve and some of the constituents of the filling material are stimulating pain as they find their way through the dentinal tubules into the nerve chamber. Another possibility is that a composite resin material was used (white filling) and as it contracts when cured (hardened) it pulls against the walls of the cavity which causes pain. One final posibility is that you may have a
fracture through the tooth. I know you say this was ruled out, but in fact it is very difficult to rule out fractres in teeth. They certainly dont show up very well on radiographs (xrays) and they are hard to identificy clinically (in the mouth) unless they are extensive.
I would like to see the radiographs if possible. Solutions to the above problems involve removing the existing filling, check the base of the cavity, placing a sedative dressing in the cavity for a week to see how things resolved. This sedative dressing is made of
Zinc Oxide Eugenol. If this temporary dressing works, then we can confirm that the pain is tooth-borne and a result of the size of the filling and its proximity to pulp (nerve chamber). If the temporary dressing does not relieve the pain then it is likely that the pain is either due to a fracture or no longer tooth-borne and the pain involves problems with the periodontal ligament (the tissue surround the tooth).
2-
If the pain originates from the surrounding tissues it means that your nerve is damaged beyond repair and their is resulting inflammation in the tissue at the end of the root. Typical symptoms of this include, continuous pain,
throbbing pain, pain when pushing the tooth down into the socket, mobility of the tooth, swelling in the gum, etc. To treat this, one would have to undergo
root canal therapy to remove the nerve tissue in the camber and canals and replace it with a resin material. This will then resolve the inflammation around the root of the tooth. An alternative and more definitive and more successful treatment option is to extract the tooth. For this we would have to be confident that the tooth was indeed non-vital (dead) due to irreparable damage to the nerve.
I would like to know the following:
1-What the xray looks like?
2- Does that pain wake you up at night?
3- What sort of pain - stabbing, shooting, dull ache, throb?
4- Is the pain continuous?
5- Does anything make it better?
6- Is it worse at any particular time during the day?
Lets hope we can come closer to finding an answer for you.
Best wishes.