Two crowns now root canal on same tooth

[Baddad]

Two years ago my dentist said that I had minor decay on a tooth but nothing that needed attention at the time, he Said that we would keep an eye on it. Since then I have been to see him numerouse times for regular cleanings and exams plus some other minor work. At no time did he mention that tooth. 3 months ago after a regular cleaning he said that not only did i need a crown on that tooth but the decay had spread to the tooth in front of it and it also needed a crown. To make a long story short he gave me a discount and we did the two crowns. After two months the original tooth had not settled down so he decided to redo the crown. Now two months later I still cannot put any pressure on the tooth and he says that I need a root canal to fix this. What should I do

 

[Bert]

Apparently there was negligence. X-ray might have been a better monitoring option.
Now it is too late.
It is hard to say if you really need a root canal treatment. Not enough info given. But it is possible. But for what I get from you, it is likely that your crown is or was high. That would have cause a over charge(weight) in this specific tooth and therefore injured the tissues close to the root tip, causing pain when you bite.
Best of luck,
Bert