No sensitivity should be felt after a root canal treatment
. Be sure of the fact that no other teeth is affected, coz many times it happens that the adjacent Tooth or some other tooth in that side maybe affected and you might be under the impression that it is your root canal
tooth. If your opposing upper tooth is also paining now, then you may have to get some treatment for that too. If it is jus sensitivity then probably some desensitising agent may help. please be clear as to what kind of pain
you have in that tooth and get it checked too for any decay. I didn't get it as to which tooth is loosened. As far
as the caps are concerned, they should not be needing any replacement I suppose.