These are the details I can remember: there's this boy who is bullied at school and one day the accidentally pushes a girl (I don't remember if she bullied him or not) and she falls, hitting her head on a rock and dies. Then, his mother is ashamed of having a "killer" in the family and locks him in a room and builds a concrete wall in front of the door. He spents years and years in there and then his mom dies and there's no one left to let him out. I also do not remember how it ends, if he gets out or not. It was a very depressing movie.. If these details can help, I would like to know the name of the movie. Thank you!

Bad Ronald

Thank you very much! That's exactly it.

You're very welcome.