Tor.com consistently post excellent short stories. I highly recommend reading ‘Foundation‘. It’s by Ann Aguirre.
‘In Ann Aguirre’s award-winning novel, Enclave, humans have taken refuge in colonies below ground. “Foundation” is the story of what drove them there, told through the eyes of a teen who would later have vast influence over the fate of many, and who gave his heart to the one person who needed him most.‘