The constitution does not mention separation of church and state. That is the construct of a group of judges in 1948. The Constitution does not mention freedom from religion but rather freedom of religion.
If you do not have a religion that's OK no one is going to make you have one. By the same measure, you are free to hae one and express it. At least you were up until 1948 . Ever since then there has been a constant eroding of the Bill of Right into the Bill of Privileges. Soon it will be the Bill Of What Used to Be.