(I am a girl, this is my friend's profile)

I have this pain in my right breast and my upper back, I can't tell where it is because it radiates throughout the bottom of my breast and the further right side. There is no lump and I don't know why my back is hurting. What could this be, do need to get this checked out?
This started yesterday and I think it was worse, but I THINK the pain is starting to subside a little. What is this and do I need to get this checked out?

I doesn't hurt when I breathe or move my arm, only when I get up or do certain movements.
SORRY, I MEAN LEFT SIDE, NOT RIGHT SIDE!!