Some people just do that more than others. It's no big deal.
If it's a lot, it's a problem. You should get it checked out then. It could be serious. A solution, tell your doctor and get some medicine. I know it helped me. Thank God.
Only if you feel bad about it as when you sleep it is hard to control such things.
No I don't think it is unless you wake up with a sore throat. You might consult a doctor and I'm sure he can help you with that problem if it bothers you.:)
I drool in my sleep too, but I don't think its bad but I would try sleeping on my back- it might acctually help.