Hi, you need not to worry, just inform your dentist about the pain, he'll either reduce the tooth so that it do not contact with opposing tooth. After root canal Treatment pain is expected for few days. Best of luck.

Hello, root canal undergoing tooth will be tender due to inflammation. Also need to whether your dentist has relieved the tooth out of occlusion which means out of contact with opposing tooth. Finally, my personal opinion is I wouldn't recommend a root canal for third molar when your first and second molar are in good health. Take care