There really is nothing quite like the power of pastry. It's that wonderful, feel-good moment of a fresh, hot, cookie. You can't beat it. And there are people who feel called to produce that kind of wonderful experience that comes from the combination of flour and sugar and butter and chocolate and fruit, and it's just an incredible desire to make people happy with those kinds of ingredients. People like that often follow their passion to become pastry chefs.
A pastry chef is someone who's responsible for all of the pastry in a restaurant. If a restaurant is making its own desserts and they're freshly prepared, it's the pastry chef who works with the chef to determine what should be on the menu and what people should enjoy for dessert and how it should fit in with the overall concept of the restaurant. Also, the pastry chef may provide the breads that are needed for a restaurant, whether it's the rolls or the buns that are used for a hamburger or for another dish on the menu.
Pastry chefs work with very exact measurements, a very exact understanding of the chemistry involved in the rising of the product or the production of the product or the perfect glaze or the temperature of the sugar. All of these things are very exacting, and to be a pastry chef you need to know your stuff. There is nothing casual or spontaneous in a sense about being a pastry chef. It's an exacting world, and you need to be very well trained in it.
To become a pastry chef, it would be best to go and find training at a culinary school in pastry production and in the pastry arts. You will learn a broad range of skills and understandings that you will need if you want to become a pastry chef. The best way to develop your skill and to develop your understanding is to spend time working as a pastry cook, a production cook who produces the basic building blocks of the plated dessert in a pastry kitchen, in a restaurant.