Tooth pain !

So I had a root canal done to a front molar about 4 years ago. It started hurting or feeling weird after experiencing sinus infection. I went to two dentists that did x rays and a examination that day it looks good. It almost feels like it’s going to fall out. It’s not loose really, it doesn’t hurt to press on it and it doesn’t hurt to eat AT ALL. I keep messing with it daily to make sure it’s not going to fall out. This has been going on for 3 weeks. What do you guys think? Was it from sinus pressure and now it hurts bc I keep messing with it? Would the dentist be able to tell if something was wrong from a x ray or examination?