1.   His jaw ached and he realised that he was grinding his teeth, so he released the muscles and tried to relax.

2.   She might be so bored that her jaw ached from trying not to yawn, but Nicolo -- Nicolo looked as if he were about to explode.

3.   Behind my forced smile, my teeth were clenched together so tightly that my jaws ached.

4.   After Billy began chemotherapy in August, his hair fell out, his jaw ached and he was often left with a metallic taste in his mouth.