Tattoo placement and pain

🏳️‍🌈Laney🏳️‍🌈 • 🤗🤗🤗🤗
So I've picked the tattoo I'm getting when I turn 18, and I'm torn between on my shoulder or my rib cage. I'm kind of chubby so it could wrinkle when I sit certain ways if I don't lose weight before hand. 
What are the pain levels of the two places? 
This is the tattoo I want