Hi Bigsis and welcome! I would guess that your doctor is thinking of doing SARPE. You can get a lot of expansion with SARPE and don't need any type of bone implant. With this type of surgery they fracture the bone and you open a palate expanter a bit each day - the bone fills the space in as you go. There is a ton of info an the SARPE thread....it is like 70 pages long so go get a cup of coffee and a sandwich before you dive in.
Go visit several orthodontists and get their opinions before you start to draw any conclusions. It is important to be an informed consumer. Write everything down and then come back online and do your homework. This is a decision you want to feel really good about before you do anything.
As to how bad surgery is...it is different for everyone.
Most people don't have a lot of pain, both because nerves are moved around and there is a good deal of numbness, and because there are excellent pain killers out there. I had SARPE 6 months ago and I used Advil and Tylonol. The hard part of this kind of surgery IMO, is the discomfort from swelling, the food restrictions, and the ongoing numbness.