Do I need a root canal?

Hello! I had a filling done for a deep cavity in my upper right second molar, on my right side, about a month ago, and I still feel sensitivity in that tooth when I eat/drink hot/cold things. Without any stimulus, the tooth is normal, I don't feel anything. But with hot/cold stimuli, I feel a pain that lasts like 2 or 3 min. Its not a pulsating pain, but it does last a while. Some say that after 2 weeks everything should be fine, in other places I've seen that the nerve can take several months to heal. I'm 34 years old and I also had a wisdom tooth removed that was next to this tooth in the meantime, so I don't know if that could also be affecting its sensitivity/making it take longer to heal. Should I wait a little longer to see if it heals? Or is it necessarily a case for a root canal? How can I know for sure? 

PS: When I had the x-rays done, the tooth was filled by an dentist, but when I came to a wisdom tooth specialist, she sayd the filling was not well made and there was still cavities in there, so she redid the filling, and told me it got very near the nerve. The wisdom tooth next to it was removed, and the lower one on this side was too. She said I also have cavities in the other molars, on my left side. Waiting to get that fixed to pull the remaining widom teeth. I don't drink and smoke eventually.