Hi..
If the doctor leaves your one ovary intact, no you will not experience menopause. However, if the ovary is taken out as well, you will experience surgically induced menopause to some degree. Everyone is different. Some people need hormone replacement therapy, some do not. There isn't really anyway to determine how much of an effect it will have on you. I've had two aunts go through surgical menopause: one never even noticed the change, the other thought she was "going to die", ie, hot flashes, mood swings, etc.
As for being painful, I assume you mean the surgery itself. Yes, there is pain involved. There are different surgical techniques used, but they all will include some pain. You'll be given IV pain medication while in the hospital, then switched to an oral form. You'll probably go home with a prescription for pain medication. There is a wealth of info here:
http://women.webmd.com/tc/Hysterectomy-T...