Too bad dentists don't get on this site. I had this problem after getting composite fillings 2 years ago. Four out of four molars hurt after composite fillings.
Here's my 2 year update, and my conclusion:
Tooth 1) Dentist decided to redo it because of the "buble theory". Drilling out the filling took up all the remaining enamel and I ended up with a root canal. Root canals are great, they fix everything. But I doubt they are really needed.
Tooth 2) Dentist did some reshaping. No real benefit. Gradually pain went away in about 3 months.
Tooth 3) Did nothing. Gradually pain went away in about 5 months.
Tooth 4) I got tooth reshaped again and again and again... eventually I just had the dentist adjust it as part of my 6-month checkup. Pain finally went away after two years.
Now I'm back on this site because my dentist redid tooth 3 due to alarm from the density sensor tool (suggests decay). Now I have the pain again after 3 weeks.
Conclusion: I'm actully in shock that this issue is so pervasive yet dentists are not doing anything to understand what is going on. They sluff off easy answers like bubles or high spots or grinding in sleep, and many other BS stories. I suspect its due to the composite resin causing stress when it cures. It is well known that resins shrink when they cure. I bet this cause stress in the tooth that irritates the nerve. This stress eventually relaxes out. I think the solution might be to remove excess filling (not the high spots, but any thick areas). Anyway, just a wild theory that will never be read by any dentists.