I am looking for a short story I read a couple of years ago. As far as I remember the plot goes like this:
A person with a brain tumor gets treated with an experimental treatment, that infects the tumor with a virus.
Once they kill off the virus, and with it the tumor, she is deemed healthy. Unfortunately, as a side-effect the treatment removes all the parts responsible for the feeling of joy too and leaves her in deep apathy.
Some time later out of despair she takes part in an experiment and receives an implant to stimulate her brain to effectively create an interface to choose how much joy she feels in a given moment. Then the story goes on showing how she tries to tune this interface and her emotions.