Lululemon Tank- built in bra, open back, size 4

Love love love this tank, but it’s too tight on my chest area! It’s a light pink color and the built in bra is black/gray! Super light weight & super cute! I was bummed when it didn’t fit. It’s a size 4, so fits like a small. If you are a medium and have small boobs, it would most likely fit. I wear a medium and it fit everywhere, but my chest area! It’s in great condition!