It can come from sleeping on your side because of the pressure on your jaw. I would recommend finding someone to massage your neck, head and face
Sounds like an abscess tooth. Are your gums swollen or your cheeks puffed out like a chipmunk? You should go to the dentist. Being pregnant isn't so great on teeth. Take extra care of them.
There's a condition you can get in pregnancy that effects the jaw. Your more susceptible to it if you've had a clicky jaw or pain before pregnancy. If you go to your dentist he can check it out and give you a mouth guard to sleep in to reduce it and talk to your ob about appropriate pain killers.
I have the a similar problem. I have to wear a night guard/splint or my teeth and jaw hurt so bad when I wake up, even if it was merely a nap! Your dentist can make you one, or you can buy the kind that you mold yourself and they say the last 6 months.
Something about the relaxin hormones. I can't remember the name of it but I'm sure if you google it you can see if that's what you think it might be.
If it is an aabses do you reckon there's anyway I could be knocked of to have tthe tooth out ect..as I want to avoid a dentist as I had a huge abses last year and I actually had nightmares all the time after as the injections dont work with abses!!! Is there any pain relife other than paracetamol I could take