All who do iniquity, is a collective reference to all sources of trouble, not necessarily just from people.
Pressures come to us from this world in many ways. Most of our trouble comes into our lives because of our own incorrect thinking and thoughts, originating from other people, from the systems and bureaucracies that operate in the world, and from natural disasters regardless of its source (weather, genetic, etc.).
But to the believer who is obedient toward God, the believer who does not react in sin or hate or blame or search for excuses or retaliation or runs away from responsibility and so forth, then there is an assurance that God will hear the prayer.
Pressures come into our lives from many sources, and most of them are mere tests to see how we will react. Most people fail because they get upset, and allow hate and anger and bitterness and blame toward others to enter into their life. For them, God does not hear the prayers and for them the frustrations of life only continue and/or grow until they either crack or repent. Stubbornness and arrogance is a cruel lesson to learn by.
The previous verses describe the troubles that can come into our life, making us miserable and fill us up with despair.
This verse instructs that there is an answer, but only if you do not give in to the temptation of anger and hate and so forth.
Very few can stick to their guns, because God can apply pressure, and keep on applying pressure, in order to prove your metal or lack of it.
This life is not your destiny nor your purpose. However, too many make the details of this life into a do or die event. They cry out when plans, their plans, do not come to pass. And that occurs because their plans are not Gods, but their own.
And so the pouting and hate and even sabotage of their life and their family and all that exists in their life, becomes more important to them than simple truth. They dislike something and therefore will destroy everything, rather than humble themselves.
But for those who adapt, persevere, humble themselves, even though they do not have everything that they want out of life, and look to Gods plan, and wait on Him, then answers do come. But they come in Gods timing, not yours.
End of study