Pain is a message in the brain. It says "this is bad!" so we can act and avoid something.
Pain lets us avoid damage. So animals with pain will have more offspring than animals without pain. So anything that evolves to survive (i.e. competes for limited resources, and reproduces) will feel pain.
If pain distracts us from other activities then it reduces our ability to survive. So pain will on average not be distracting. But that is only an average: individuals will vary.
The universe is unpredictable, so some pain will be horrific and unacceptable. And, thanks to randomness and ignorance, innocent beings will suffer.
So as long as there is the need to survive, innocent people will suffer unimaginable torture. That is part of the package. You want to survive? Then you are choosing unimaginable torture for some random person (and if you are unlucky maybe yourself). Even if you spend every waking moment striving to end suffering, ignorance and randomness mean it is always part of the deal. as long as things need to survive, random pain (some of it horrific) will exist.
If you are in extreme pain then obviously your top priority is to end that pain.
If you are not in extreme pain, but you have empathy for others then obviously your top priority will be to end their pain. But not in a way that accidentally increases pain: so this is not an argument for suicide or for blowing up the world. Life evolves to be very good at surviving, so any attempt to destroy it will tend to lead to part of it surviving, but in greater pain than before. So violence is not the answer.
What is the answer to pain? Peace. How do we achieve peace? That is the topic of the page on consciousness and happiness.