Can you get a fracture /cracked tooth doing a cavity filled?

Went to the dentis to get cavities filled,pain started along with headach,Dentis reset my bite in mouth,and pain went away.The following sat,pain started again.Went back to Dentis he did xray and found that i had a fract/cracked tooth where he filled the cavity.Now hes saying i need a crown in that area,and i must pay what my insurance wont pay.I feel thats not right and that we should split the cost he could have caused the fracture/crack tooth.Im thinking if it was already there i wld have had some pain before he did the filling.What do u think?