I recently got a crown on the upper left rear tooth. Now I have jaw pain and I have bitten my cheek.

From the sound of things, I would recommend returning to your dentist to have your bite adjusted again.  It is rare, but it is possible that another adjustment may be needed.  If it were just your tooth bothering you, then I would warn that you may need a root canal, but since it's your whole jaw, it is more likely that it is still your bite.  If pain persist after adjusting your bite again, then you may need to look into redoing the crown or having a root canal performed.  Good luck and I hope this helps. Follow me if you have
more questions.Sarah Thompson, DMDO Fallon, Illinois and St. Louis, MO

There are several reasons a jaw can hurt after placement of a new crown. The first is that the crown is contacting to opposing tooth too heavily. This can make your tooth and jaw sore. Another cause for jaw pain could be having no contact with the opposing tooth. It is also possible that you could need a root canal and are getting referred pain. The important thing is to revisit the situation with your dentist.

You bite your cheek because of improper design of the crown you have. Probably if you look at the mirror while keeping your teeth close, you see the cheek surfaces of the crown and upper tooth are at the same level to your cheek. Normally lower teeth closes more inner than upper teeth. if you check the other side you will see the right position of upper and lower teeth according  to each other.