Pain in Permanent Crown

I had my permanent crown installed on Monday July 9th.  Before that I had a temporary filling then a temporary crown.  There was little to no pain with the temporary filling.  With the temporary crown I did have a little temperature sensitivity.  I deliberately didn't test the temporary crown (chewing on the other side of my mouth most of the time).  

The dentist said that could be an indication that I might need a root canal.    She poked and prodded but no pain from that.  She said I had 3 choices, put the temporary back on, do a root canal, or just "go for it" with the permanent crown.  I chose the latter.  She also said they could always do the root canal through the crown.  That sounds scary to me.  Is that a good idea?

Just before she put the permanent on she said that people who had temperature sensitivity from the temporary usually had more temp sensitivity from the permanent cement.  It felt more like someone stuck a knife in my jaw!  Yes I told her immediately and aske how long the pain would last.  She didn't know.  After a few hours it merely felt like someone had a pair of needle nose in there and was squeezing for all they were worth.

Ibuprofen is working but the thing is I still have the pain.  It is not as bad, it merely feels like someone is squeezing moderately with the needlenose.  If I take 400mg of Ibuprofen the pain dissappears for about 12 hours.  I took that yesterday afternoon about 2 and woke up with the pain at 2 this morning and had to take 2 more to go back to sleep.  Should I go back?  Should I get a second opinion?