Extreme Crown Pain after a year. HELP

[TerrahB]

I had a crown put on last March/April.  Its the fromt tooth on my upper mouth.  Actually I had a crown put on the other front tooth and the one next to it.
I have 5 crowns total 2 of them which were placed on back molars.

Anyways.. Im in so much pain.  Its throbbing pain.  I cant even bite down or put ANY type of pressure on my tooth without me being in extreme pain.  I do have a sesitivity to hot/cold (my teeth always have had this sensitivity).  What Im experiencing is pain.  I just noticed it a few days ago.  It started off as a little discomfort now its full blown pain and the worse is, IT WONT GO AWAY. Its constant.  I have had this crown over a year and never hade a problem with it until now.  It hurts the worse toward the bottom of the crown (not top where my real tooth is underneath)  
Can you still get cavities with crowns???What do you think is wrong. Does it sound like I may need a root canal??
Please Help

[mike1105]

could be anything from nerve involvement (possible root canal) or periodontal involvement (bone and gum tissue around the tooth or teeth). I'd see a good general dentist or perhaps you may want to enroll as a patient at a dental school. No way to diagnose your problem over the internet but you should not be in pain every day.

[NellaF]

It could be an abcess (abscess) under the crown. If it is throbbing pain, and sometimes you get sick w/ no explination.... like you just want to throw up a little for no reason all of a sudden... it is an abcess (abscess). It will prob. need a root canal and so much more.  :p