Your birthday Torah portion is the weekly Torah-parsha (Torah-reading) which occurs on the first Shabbat after (or on) your birthday. Usually we calculate this on the birthday of your bar mitzva year, not the year you were born.

There was a time when the Jews were subjected to a persecution which included a decree that they not read from the Torah. In order that the weekly Torah readings not fall into disuse, the Sages instituted a custom to read a portion from the prophets that was a similar subject to each week's Torah reading.

The Bar Mitzvah ceremony normally takes place in the synagogue on a Saturday morning when the weekly Torah portion is read.

The Torah is divided into weekly readings, called "parshas". One system divides the text so the entire Torah is read in one year, another system is based on a three-year cycle. So at least in theory, all portions are read in equal amounts.

A dvar Torah before Musaf on Shabbat is a way to enhance the spiritual experience of the service by providing insights and reflections on the weekly Torah portion or other Jewish teachings. It helps to connect the congregation to the themes of Shabbat and inspire them to deepen their understanding and connection to the prayers they are about to recite.