I had a difficult lower molar extraction 1 week ago - roots fused to the bone. severe pain feels like a bone fracture. could i have a cracked jaw?

Possible dry socket: It would be nearly impossible for the jaw to break during a routine extraction. The most common cause of severe pain after an extraction of molars is dry socket. If the tooth was fused to the bone, a surgical drill would have been used to remove bone which also can cause additional post operative pain. You should see your dentist for a post op exam to address any possible complications arising.

Ouch!: I expect you've informed the dentist (or will ASAP) - that's the best person to evaluate your healing and it's part of the responsibility of the extraction. Ask your questions while there and see it through until you are confident and satisfied. Dental work can be stressful in so many ways - treat yourself well through this time. Good diet, rest, leisure, etc. Best wishes!

Doubtful: You had a difficult surgical extraction which necessitated the cutting of bone, gum tissue, and then sutures to close the wound. Even though you feel a week is enough time for this to have healed, it will take longer. Your surgeon should be advised of your pain.. you might have an infection.