Osananajimi Doushi ja Irarenai

Shiori Mizuno is a university student, and Yamato Mochizuki is her childhood friend and next-door neighbor. They used to be good friends, but he confessed to her and caused a rift between them. Shiori was devoted to track and field at the time and, while Yamato was her biggest supporter, she could only see him as like a little brother. She distanced herself from him by going to a boarding school, and that was that.

Several years later, however, losing both Yamato and track and field made Shiori realize how important he really was to her. Shiori desperately wants to go back to the way they were before, and is prepared to accept anything if it'll change his heart... but their relationship becomes solely physical with no feelings from him, and the pain drives her to tears...

(Source: Renta!)