Stronger (2017) on Netflix

Plot summary

At a Boston bar, Jeff Bauman runs into Erin, an ex-girlfriend who admires his kindness but is tired of waiting for him to commit. Jeff works the deli counter at a Costco and lives in a small apartment with his mother, Patty. Learning that Erin is running the Marathon for the hospital that employs her, he collects donations from the other patrons and promises to hold a sign at the finish line. On race day he arrives just before she does, and a bomb explodes where he is standing. He wakes in a hospital with both legs amputated above the knee, tells his brother he saw the bomber, and Patty calls the FBI.