Update multiple values in all posts/pages by editing a single file or mask?

I want to show different information about some services on my website. These values change very often and I can’t update the posts manually:

I need to be able to edit the ever changing values within a single file / or mask cause there are hundreds of them.

In every wordpress post I want to use a shortcode or something like that to show
“service_a_features”
“service_a_time” at the given position within the text.

How could I accomplish that?

Before WordPress I just used a file called “update.php” in which I had defined variables. I then included the update.php in all of my webpages and used echo $service_a_price to show the the value.

I need to do this with hundreds of custom data fields. How can I achieve my goal?