Had New Crown Replaced on Back Molar in June. Also Had Root Canal Done on It Several Yrs. Ago. I've Been to the Dentist 5 Times?

in the last 2 weeks. took x-ray, thought there was an infection in it, but there is not and he said the root canal looks fine. It's the gum around the crown that seems to hurt the worst. He said it's because I'm grinding my teeth at night and that has atrified the ligiments. the bridge right next to the crown felt loose to me, he checked it and said it wasn't the birdge but the teeth underneith, all due to clinching and grinding at night. Could this be an ill fitted crown? Have had it filed dwn.