Hello mam.. Infection heal means do u mean root canal treatment of that particular teeth?? if the root canal treatment has done then the teeth wont be sensitive either....you need to go for bite adjustment of the crown...if root canal is not performed then the tooth which is crowned needs to remove and root canal has to be performed on that concerned tooth.....sometimes you can also wrongly perceive the pain as sensitivity ....so also check for any re infection if the root canal is performed in that tooth through x-ray examination....also check for sensitivity in that filled teeth too.... sometimes nearby sensitive teeth also be cause radiating pain .... clinical examination is necessary to rule out the cause and management

If the crown was done after the infection healed, do u mean, a root canal procedure was performed..?? If so, then that tooth should not be sensitive, to hot or cold and  sweet or sour..unless no root canal was done.. Or, do you mean, the crown is painful on biting or chewing? If so, then maybe the crown needs some bite adjustment.. If you have a filling done in a tooth, that tooth could be sensitive due to various reasons. You should visit your dentist, And, till you get an appointment, try using sensodyne Rapid Relief toothpaste on that specific tooth, and see whether that helps..

Try to avoid too hard food items and visit ur Dentist to get the X-ray done