After a crown on my lower back right I keep biting my cheek. Why is this happening and how can it be fixed?

Hello,
Sometimes when you get new crown you have to wait some days to adapt to the new crown but in case you continue biting your cheek you have to chance it or try to adjust it.

Good luck. 

This is a fixable problem. The cheek is getting caught between your teeth because the lower crown is situated too far out towards the cheek. Have your dentist cut back the surface of the crown closest to the cheek and the situation should resolve itself. It may not be an instant fix because if the cheek is swollen you may be more prone to biting it for another week or so.