My dentist says i need root canal therapy and i don't feel any pain! should i consult another dentist?

Maybe.: If you have any doubt that your dentist is right or not, a second opinion is wise. I will say, though, that not all teeth that need root canal are painful. Some simply show on an x-ray that the nerve died and abcessed!

Pain not necessary: You may need root canal therapy without having any pain. High blood pressure and diabetes have no associated pain, but do you wait for a stroke or heart attack to seek care? If you really do not feel your current dentist is correct, then seek another opinion. But most likely he is right.

Specialist: See an endodontist. They specialize in root canal treatment, and would be best at evaluating your situation. Worst case scenario your need is confirmed and you are in the best hands possible.

Not necessarily: Were there any other things your dentist could show you. For instance, was there an x-ray with a visible abcess? Was there visual decay all the way to the nerve on that same x-ray? If there was nothing concrete they could show you, then yes consult with an endodontist.