Generally a tooth with a vertical fracture is hopeless and should be removed. The enamel/dentin that make up the hard part of the tooth do not have a blood supply and therefore cannot heal by the same methods as bones. The pain decreases because the pulp (nerve) of the tooth will...
If the root canal treatment was done properly with a rubber dam and the canals were cleaned and disinfected and properly sealed, then you will probably NOT have any problems.
Files can break withour warning and this happens all the time. Some can be removed, others can by by-passed and...
It sounds from your description that the tooth is not restorable and needs to be extracted. I would see a dentist ASAP and get an opinion, the longer you wait the greater the chance that you will have to have the tooth extracted