I had a large filling in an upper back molar which caused tooth to crack and break off. I had a root planing and scaling and a temporary crown put in. After extreme pain, tooth was examined and temporary crown taken off, cleaned out and put back on. A week later, I still have pain in area and am still waiting for permanent crown. Am concerned that permanent crown will be placed and pain will still be there. Do I need a root canal?

Possibly, maybe more like probably. Pain alone is not enough to determine what you need, however, online - X rays are. Scaling and planing are merely removal of plaque and calculus.
Personally I would find an endodontist for examination and possible root canal, not a regular dentist, especially of a molar. There is a lot of skill and precision required to do a molar root canal (multiple roots), and not doing it exactly right leads to all sorts of problems.