All medications have side effects. You should ask your doctor before using any new kinds of medication and be well informed on what the side effects might be.
Jaw pain in your face specifically could be caused from many things, ranging from teeth grinding when you sleep, to gum disease! It's hard to know, and it would probably be best to consult a dentist.
Face pain may be caused from having sustained an injury to the head, like getting hit in the face with a ball, or for other reasons like a nervous disorder or an infection.