Pain after crown on teeth implant, I'm concerned. What's wrong?

Sounds like you need a small adjustment to the tooth that is opposite the crown.  The pain seemed to be the result of the crown placement, so an adjustment would be the first thing to try.  It only takes about 5 minutes in the dental chair and doesn't even require a numbing shot.  Usually very fast and pain free.  I hope this helps.  Click save under my name below if you have more questions in the future.

From your description, my first thought would be muscle pain which causes pain when opening or chewing.  This can be caused by your bite being off with the new implant crown.  Even the occlusion (bite) being off a little bit on the implant can cause big problems with opposing tooth pain and muscle issues. I would recommend returning to your dentist to discuss.  Have your occlusion checked and adjusted if needed.  Your dentist may also recommend a night guard to wear and protect you investment.