YEP! Sorry to say but that definately sounds like TMJ!
You need to speak w/your dentist & possibly try out the new partial & see if that helps any.....if the old partial was bad enough it could have made your jaw set crooked in the joint long enough that it did some damge there & when pressure was applied to that area in order to get a new impression I would have to believe it was a dsfinate joint problem going on there! Ibuprofin is good for the joint pain & you can check out the TMJ site they have some exersises on there that are very helpful! Heat also works well for the pain! 20 minutes on & 20 minutes off! Also ask about a bite splint! They work wonders for TMJ!
Good luck & take care!