I am trying to remember the name of a shoujo manga. Here is what I can remember:

-romance where MC initially has hard time with main guy
-main guy turns out to have a painful past
-in past, a girl confessed to main guy, and after he refused, she fell, hitting her head or neck
-second girl now has scar, and main guy feels responsible
-in one scene, a ball comes flying at both MC and second girl. May guy protects second girl
-I believe in the end MC and main guy get together

Can anyone please tell me what they think the name of this manga is?

Mune ga Naru no wa Kimi no Sei ?

That's it! Thank you very much