Having extreme tenderness after root canal completion, is it normal?

Possibly: After the root canal treatment acute pain may occur due to minor reactive swelling under the tooth involved. This swelling pushes the tooth into the opposing arch and results in pain every time they touch. Opposing teeth touch every time you swallow (a few times each minute). This problem may be easily fixed by the dentist that treated you. Give your dds a call to re-examine the area.

Yes: Yes, tenderness for 2 days is normal. Consult an endodontist if your symptoms persist past 2days.

Unfortunately yes: Some tenderness is very usual, BUT after 3-4 days the tooth should begin to feel better, by 2-4 weeks it should feel normal. IF NOT, call your dentist for a reevaluation!