I have 10 crowns for 7 years. All of a sudden cold is excruciating. No bumping nothing unusual. What is this?

This can be due to receding gums,crowns might be ok. The only thing is that if the gum receeds there is a big chance of having the root exposed, and this will make the tooth to be sensible. Of course Xrays needs to be seen, but if it is what I think, based on your description, then you will need or either change the crowns or perform a gum technique to restore the sensitivity. I hope this helps.