I've never had a cavity. A few years back I got an infection and had a root canal though. It was smooth and I've never had any pain or problem since. Sounds like having a crown sucks though. Ouch.Something similar happened to my wife. Hard to pin responsibility down and get them to pay for their mess up.
I agree with @TODAY in that u want to treat that as soon as possible.
Sounds like the nerve is simply very close to the surface.
I’ve definitely experienced sensitivity for that reason.
Root canals are catch 22s because they essentially kill the tooth. However, I’ve had a couple and I love them because I can’t feel hot and cold.