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

A week ago I got my permanent crown put on,the temporary one caused me no problems.When i went to have my permanent one put on the dentist said it didn't quite fit so he filed down the tooth above it.Now i seem to have a problem with biting my cheek,would happen only once or twice a year but now it's a daily occurrence. If i tilt my head to the right i can bite up and down with no problem but if i tilt to the left i can feel a piece of my cheek in the way as i bite downward,how can this be fixed?