Kyou kara Ω ni Narimashita.

Ordinary university student Kanade is a beta. He secretly holds feelings for his neighbor and childhood friend Munechika. However, in this world, the typical trend is for an alpha and omega, and two betas to pair up. Because of that, Kanade thinks he's not a match for Munechika who's an alpha, and stays with him as a friend. However, one day, Kanade feels a weird discomfort in his body...

(Source: Kadokawa, translated)