Do root canal problems show up in xray

[Macleod1174]

Last Saturday I was feeling some discomfort with one of my teeth. Tooth has a crown on it. I was chewing on a piece of steak and it felt sore. The tooth felt I sore on sat, sun mon and Tuesday. I went to my dentist on Tuesday and they didn't see any thing wrong on the X-ray but when she taped the tooth with one of her instruments it felt a little sore So she made me an appointment with an endodontist for a root canal on Friday. Well now my tooth no longer feels sore or hurts. If there was a problem with the roots on my tooth wouldn't it show up on an X-ray? I am not really sure what to do now.