Hello & welcome,
You could have done more investigation before undergoing the extraction of the tooth which was treated by Root Canal Treatment
like doing x-rays at different angles.
This is because, you might have found this culprit canine tooth
at that time, treatment of which could have solved the problem.
Now for canine, if there is nerve exposure which is obvious after severe caries, if your dentist
cant find any thing abnormal in x-ray, then you can go for having second opinion
Tooth with nerve exposure should be treated by Root canal treatment after diagnostic radiographs are taken to confirm the extent & destruction by caries followed by Crown placement.
Antibiotics & Painkillers are necessary though they won't relieve your tooth ache
completely so as to avoid the opened nerve endings & pulp tissue to get infected.
Keep your oral cavity clean with proper & regular cleaning habits to avoid further decaying of other teeth.