I Am a Curious Person

I am trying to learn about other people's depression/self harm stories so I can find out if they overcame it and how. But on YouTube one of the vids I watched ended with "don't ever start self harm, it's addictive". The question in my mind is how is pain addictive, I should make you feel worse. I feel like if I was going to have an addiction, it would make me feel better. How does self harm make one feel better?