Tooth with crown is throbbing. My cheek is swollen and I have a splitting headache. What could cause this?

Tooth with crown (I've had the crown over a year) is throbbing and has caused my cheek on that side to swell. I can feel it messing with my sinuses and has caused me a splitting headache. I have had this happen once before and went to my dentist who did the crown (no root canal done) and he filed the crown down and did not seemed concerned that it was swelling my face. Swelling went down a few days later, but it is back once again even worse. Could the tooth under the crown be infected?