Behold, the Lord's hand is not shortened, that it cannot save; nor His ear heavy, that it cannot hear. But your iniquities have separated you from your God; and your sins have hidden His face from you, so that He will not hear (Isaiah 59:1-2).
It is not that God cannot hear your prayers or that He does not want to listen; the problem lies in the individual: "Your iniquities have separated you from your God; and your sins have hidden His face from you."
It is important to understand that unless the barrier of sin between man and God is fundamentally broken down, a person's prayers are of no avail. If the sins of an individual are blocking the way, even though he may pray, his prayers are not appropriate before God, and God does not hear them.
It is no use just crying out to God when things go wrong in your life and forgetting about Him the rest of the time. A relationship between you and God must be established and then your prayers will flow as naturally as breathing, and God will hear and answer them.
To establish that relationship, you must first believe without any doubt that God exists. Then through the Bible, you will be able to see what kind of person you are before Him, as your sin is revealed to you through the mirror of His word. The next step is to allow God to solve the problem of your sin for you. When the problem of your sin has been solved once and for all, you will find that the conversation between you and God will be able to flow freely.
In John chapter 9 verse 31 it says, "Now we know that God does not hear sinners; but if anyone is a worshiper of God and does His will, He hears him."
It says very clearly here that God does not hear sinners. There is, however, one prayer that God will listen and respond to, even if you are still struggling with the problem of your sin. If you are sincerely looking for God and cry out to Him deep down in your heart, you can be sure that He will guide you to the place where you can find Him.
"Ask, and it will be given to you; seek, and you will find; knock, and it will be opened to you. For everyone who asks receives, and he who seeks finds, and to him who knocks it will be opened." (Matthew 7:7-8)
For thus says the High and Lofty One Who inhabits eternity, whose name is Holy: "I dwell in the high and holy place, with him who has a contrite and humble spirit, to revive the spirit of the humble, and to revive the heart of the contrite ones." (Isaiah 57:15)
If you have not found a definite answer to the problem of your sins, please read the books listed on this website, looking up the references in your own Bible. Before you can talk to God, you need to listen carefully to what God is saying to you. Then you will know how to respond to Him.