If I am around 5'5, what would be my chest size?
There is absolutely NO way of knowing. I don't know what makes you think every height has a certain breast size, height has nothing to do with it.
ummm... I think there is because I wanted to buy a shirt and it showed the chest sizes which is why im asking how I can know what chest size I am
Well you cant really try anything online...
Why not try them on?