How much does a chest piece hurt?

That really is a lotta ouch. If I were you, I'd get it done in several sittings. That's a lot of work. Get the lining done, then you can go back for the shading, then the color sitting. It'll be to your advantage, because not only will it cut down on the pain factor, it's more affordable to pay by the sitting. Many people do. Another reason is that you can catch your artist while he's still fresh, as opposed to wearing him out. He'll do a better job, trust me. Whatever route you take, enjoy your new ink!