The search algorithm of the Play Store factors in things other than the name of the app like the number of ratings, number of downloads and the text of the description, among others.
They also ignore some common words like:
It's therefore possible that other apps will rank more highly than yours when you search for your app name. This isn't, unfortunately, something over which we - or indeed any app publisher - has control.
The best way to ensure that your app can be found by your users is to pick a distinctive, preferably unique name, and to use distinctive words in the description.