"Pain and Glory" follows the life of a film director, Salvador Mallo (Antonio Banderas), through two main narrative threads. One the one hand, we see "Salva"'s current life - a depressed artist in his 50s, who's achieved major success in his prime, but now lives a lonely life, lacking in inspiration and abundant in illness. On the other hand, we witness young Salva's youth, where he shares a tender relationship with his mother Jacinta (Penélope Cruz), as she bends backwards to get him an education and a way out of poverty.The narrative oscillates between these two subplots to show us vignettes of Salva's life. We see him ingress in a catholic school where he stands out as a young choir soloist, while in present life, he reconnects with Alberto Crespo (Asier Etxeandia), an actor he'd worked with, and with whom he hadn't spoken for 32 years.This rekindled relationship introduces Salva to heroin, a newfound blessing that can finally cure all of his migraines and back torments. One time, while Salva is dozing off high, Alberto goes through his computer and finds "Adicción" - a deeply personal text where the Director confesses his experiences during a three year relationship with "Marcelo", the love of his life and also a heroin addict.Meanwhile, back in the past, Salva and his family move to a new village in search of a better life, but end up living in a cave with less than ideal conditions. The 9-year-old Salva befriends Eduardo (César Vicente), a twenty-something village worker who agrees to work on the cave's walls in exchange for reading and writing classes with the young prodigy.In the present, Salva offends Alberto by revealing his opinion of his skills as an actor - and to win him back, he has no other option but to give him the rights to "Adicción". Alberto immediately puts together a play where he delivers the monologue with vibrant passion. One night, one of the audience members is visibly distraught - he is Federico, the "Marcelo" of "Adicción", and Salva's life love. Through Alberto, the two reconnect and spend an entire night catching up and finding a more appropriate ending to their story, making Salva decisive on quitting his recent heroin habit.This catharsis helps Salva free himself of some of his depression, but he still suffers from chronic back pain and constant choking - something that makes Mercedes (Nora Navas), his competent assistant and probable secret lover, quite worried. In addition, we learn that Salva is still not over the recent passing of his Mother, whom he loved dearly despite her less-than-appreciative attitude towards his unconditional love and life achievements.Back in the 50s, Salva and Eduardo grow closer as the latter makes progress, and one time he draws the young boy's portrait. That afternoon, after finishing Jacinta's tile wall, Eduardo undresses to wash off his body - and the sight of his nudity, combined with the ardent heat, causes young Salva to faint.Towards the end, the two narratives finally come together. After putting away his story with Federico, Salva decides to visit a doctor and get his life back on track. He finds a mass in his throat that must be removed with surgery. Meanwhile, Mercedes discovers an art exhibition where Eduardo's portrait of the young Salva is being sold. Salva purchases it from the dealer, and discovers a sweet inscription, revealing of the boys' connection.This discovery is the ultimate riddance Salva was seeking, as he finds new inspiration to start writing "The First Desire". In the end, we realize that the whole 50s storyline wasn't set in the past, but actually in the future - it was the film set of Salva's homonym film, where he finally finds closure through the relived wonder of his childhood and his connection with Eduardo.