Please tell me, are root canals a long and painful experience?

Nope. : Root canal therapy is nothing more than a "really deep filling". They only hurt if the tooth is cracked or already infected; the treatment is done with local anesthetic so most patients just feel bored. Many patients actually fall asleep (and many snore!) because, as a patient, it's pretty boring!

It doesn’t hurt: Root canal treatment is done under profound local anesthetic. It doesn’t hurt more than a filling or any other dental procedure. Root canals also do not cause pain, they ameliorate the pain.