I have a similar problem, I had a crown put on my tooth about 10 months ago, it became wobbly recently, I've got a new dentist, so he took it out and glued it back in. Ever since I've had bad discomfort with it. It is not level with the rest of my teeth. At the back, my real tooth is exposed causing severe sensitivity to it which is odd as I've had a root canal so I shouldn't feel anything. Overall it feels out of place and my dentist said if it comes out again then I'll have to have a denture but I reckon he has put it wrong so hopefully he will just take it out and put it in correctly.
i have a margin on the back of my crown. my dentist even used a laser to reduce gum tissue to achieve this. i had minor discomfort which has been relieved by using a toothpaste for sensitive teeth. is this something that is recent? it may need to calm down or as scottma stated you might need your bite adjusted.
As long as there is no marginal opening, supragingival margin of crown is perfectly fine. Most thermal sensitivity after crown delivery result from occlusal interference, if the tooth is vital. In addition to thermal sensitivity, occlusal interfernce of a new restoration can result in soreness of tooth and/or gum, jaw bone heaviness, muscle soreness, pain or discomfort upon chewing.