Pinktulip,
Your jaw WILL be sore for a lot of the time and it will feel like your symptoms are getting worse.... Sorry to say. This just means it's doing it's job! The purpose for this is that it's not used to being forced in the correct position it should be in.
Look at it this way. Before I got my splint, my teeth were grinding at night when I slept because they wanted to be in the 'correct' position, as my jaw was in so much distress! But, my jaw was used to this position, so when I started wearing the splint it 'complained'! But it's all for the best!
I had adjustments about every 2 months. They're normal, and are required because your jaw is moving into position so they have to make the splint fit the new position your teeth are in. Does that make sense?

It is painful, I know! Everything is moving around and your mouth isn't happy about it! You might be grinding your teeth at night. I remember doing that a lot and my teeth would be in agony afterwards.
They even suggested for me, if the pain is bad to take an advil or something. Advil, not tylenol. Advil has the muscle relaxants that you want.
After I was done the splint they put me on braces which I have in now. When my teeth are ready, I will have jaw surgery as my lower jaw is underdeveloped. They could not put braces in until my jaw was stable in it's correct position. It feels a lot better now! My left jaw joint was degenerating because of my bad bite but since I had the splint in, it's much better.
So yes, I have other teeth issues... like my overbite was so bad! It was 110% which meant that my top teeth went down and PAST my bottom teeth. I also have a couple teeth that have no adult teeth under them so they are having to be careful with the braces... so that those babies stay in as long as possible.
Sorry, I talk too much! But I hope all of this helps