We all have our opinions and we all have a right to them.
If you are saying that your pastor told you that the bible teaches that one must attempt to have children because the scripture says in Gen 1:28...
And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth. ...
And also after the flood in Gen 6:1 he said....
And God blessed Noah and his sons, and said unto them, Be fruitful, and multiply, and replenish the earth.
2And the fear of you and the dread of you shall be upon every beast of the earth, and upon every fowl of the air, upon all that moveth
upon the earth, and upon all the fishes of the sea; into your hand are they delivered.
3Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.
I would say that the command to be fruitful and multiply applied to those he was speaking too and that the mission was long since accomplished.
Heremeneutics (the art and science of interpretation of scripture) has a list of rules one of them being to ask the question "Who was he speaking to, what were the historical and culture settings, how would this apply to us today etc..." Common sense I know but nevertheless they are questions that should be asked. In this instance there was a need to populate the earth. That is no longer a need and this is not still the mission of the Church. Jesus never once mentioned it as part of the Great Commission to go into all the world and teach all nations to obey his commandments and Jesus never commanded anyone to be fruitful and mutiply and replenish the earth.
Then we have Paul in 1 Cor 7 saying that for the sake of un-distracted focus on service to the Lord and the present circumstances of those in Corinth who asked him the question. it was better if they could control their sex drive to stay unmarried but if they could not to marry for it was better to marry than to burn. He does not say that children should then be the mans focus he simply said that it would be a solution to the sex issue. So yes. Paul said for the purpose of SEX one should marry and he said nothing about a COMMAND to have children in order to populate the post diluvian world.
Christians are under the God given mission to be fruitful by sharing the gospel and bringing others into saving faith of Jesus Christ. That is our current mission. You are not sinning by not having children. You are not sinning if you do.
That is my opinion on what the bible says on this topic. Have a child because you want to, not because you think it is sinful not to. Think about doing all things from the motivation of Love. God bless and may you have a whole quiver full. (I heard a quiver of arrows was 5, lol, I have no idea if it is true)