Tooth hurts, but which?

Harika

Hi, I have tooth pain at my left side, but neither me nor the dentist can verify where the pain is coming from.
Long Story. In April at a routine dental check, the dentist found that the filling of two opposite teeth (Number 5) were not sealed anymore and decay had formed under them. The fillings were 12+ years old. Okay no problem, so the upper one was replaced, but as it was quite a big filling already, not all decay could be removed else the filling would be too close to the root, and I was told to see if I have any pain, cause this would trigger a root canal treatment. No pain developed, went on vacation and had the filling below replaced in June, this was just a small one.
From this tooth then there was always a little pulling and three weeks after went back to the dentist who tested the teeth by knocking on them and using air, but he couldn’t trigger the pain but lowered the filling a bit, in case I traumatized the tooth by biting too hard. At one occasion I was chewing and pain went through the whole side. He told me not to chew on this side for some time to see how this develops.
Now at some points, I needed pain killers, with up to the full dose, morning, noon and before night or I would wake up from the pain. Also the lower tooth reacted painful to ice cream, when went back to the dentist some cold stuff was used on it and it really hurt. So the filling was replaced and I received tooth paste for sensible pain. The pain got less after that and usually would develop only later in the afternoon that I needed pain killers.
So third time back, and again all teeth were knocked, cooled, xrayed but nothing could be found. As the dentist doesn’t want to treat both teeth, or the wrong one, I am now on a mission to provoke pain on the teeth to find out where the pain is coming from.
The pain itself is mostly coming from the lower tooth, but then can move to affect both tooth or just the upper tooth or the front teeth of the side. Since then I had some “success” and could provoke pain, mostly with hot beverage and mostly on the upper tooth, but not as strong as I need to really have proof.

So I was looking through my options and those would be to really try to provoke pain and have more info for next week’s appointment.

If this is not conclusive, I could have the upper one root canaled, on chance, as both dentists suspected this one as the filling is really deep.

Or I could see a Periodontist. If they find the source, the treatment and investigation is as expensive as two root canals at my dentist with the advantage of just one dead tooth.