I don't know what to do about this filling. First high now low -- can I do anything?

Last week I went to the dentist and got 3 cavities filled.

When the anasthesia wore off, one side of my back teeth was touching together in the back, but the other side of my mouth wasn't. I had to go back and have them file it down so that it was comfortable, because it got really annoying.

Now though, my mouth is a lot more comfortable (before it was so annoying) -- BUT, sometimes now when I talk, words with "th" or "s" in them, some air comes out of the back teeth where the bite is and I make this daffy duck sort of noise -____- ... my teeth feel okay but there's this space and it happens in almost all of my conversations. If I say a long "SSsssssssss" , halfway through, the air inevitably slips out of that side of my mouth and it sounds like "SSScghghhg*gurgle*"

Do I need to train my mouth to talk differently now, or can they adjust this filling again to make it higher? Is that bad for your teeth?

I know what the problem is, too -- when they put the blue tape in my mouth to test my bite, I'm lying down. I notice that when I lie down, my jaw rests a little further back than what my natural bite is. I want to go back and have them fix it and sit up for the part where they have me bite on the blue tape. I just don't know if dentists charge extra for this or if it's something I am just supposed to live with.