Hurts when I bite down still after having a crown placed. PLEASE HELP

It's possible that the crown may be just a bit too high and that you'll need a slight adjustment to the crown to make the bite more comfortable for you.  Sensitivity after a crown procedure is relatively normal, however, and the area surrounding the tooth can feel bruised, so to speak, so it can sometimes take a week or two to calm down and feel better.  If the tooth is waking you up at night and is extremely hot/cold sensitive with lingering, sharp pain, it's possible you could end up needing a root canal.  

Please return to your dentist and have them adjust the height of the crown. Make sure it is checked 3 ways:1) Normal biting up and down on the articulating paper2) Sliding your teeth side to side when biting down.3) Chew cycle, meaning put the articulating paper on the crown and a piece of wax or gum on the opposite side and chewGood luck, it should get better soon.Charlie Janes DDSInnovative Dental of St. Louis

Post op sensitivity is common on live teeth after crowns are placed on them, You should  go back to your dentist and have him check your bite to make sure the crown is not high. sometimes when a crown is high its hard to feel it, but it hurts when you bite down on it, Hope this helps, Good luck