is there any alternative to root canal? I would love to save a back tooth with a big filling that is hurting?

That is the last resort to save a tooth. Always have them capped afterwards or it is to no avail to have it done.

I'm not a dentist, but I am a dental assistant. If you need a root canal, that means the nerve in the tooth is damaged and will not get better. The dentist opens up the tooth, removes the nerve tissue inside the roots, then fills the roots with a filling material. The space where the tooth was opened will be filled with filling material as well. Then the tooth will need to have a crown put on it to protect it as the tooth is now technically "dead" because it has not live nerve tissue in it. And the tooth will become brittle over time. So it is vital that it is covered with a crown to protect it. If the tooth has lots of decay in it, it may just need to be taken out. If it has lots of decay, so much of the tooth structure would have to be removed to get all of the decay, that saving the tooth would not be possible, that is why it would need to be extracted instead of the root canal. Sometimes the dentist cannot be sure which needs to be done until he actually starts working on the tooth and sees how much decay it has, that is why he probably told you it might be one or the other. Hope this helps you to understand. People will say that root canals are painful. The problem usually lies with the patient not telling the dentist that they are in pain. If you are sure to tell your dentist when you are feeling any discomfort, they can give more anesthesia to keep you comfortable. Sometimes the nerve is so irritated that the regular anesthesia does not work very well. When this happens, my dentist usually asks the patient just to bear with it for a moment, because he actually has to open the tooth up to get to the nerve and then inject anesthesia directly into the nerve to make the pain go away. And sometimes there is some pain after the root canal is done, but you can ask your dentist to prescribe some medication for that as well.

when it gets to that point, root canal+crown is the last resort before extraction

Have it extracted.

no