No CS Lewis is saying that God uses pain to rouse a deaf world "God whispers to us in our pleasures, speaks in our conscience, but shouts in our pains: it is His megaphone to rouse a deaf world....
Agreed; that is a quote which I particularly like.
But it gives the only opportunity the bad man can have for amendment." this quote never says that after God loves. We must be careful not to put our ideas on a quote or look into something that is not there. CS Lewis never said what you think he said
Your quote from Shadowlands;
“Here I am going to say something which may come as a bit of a shock. God doesn't necessarily want us to be happy. He wants us to be lovable. Worthy of love. Able to be loved by Him.
C.S Lewis say that God wants us to be worthy of his love.
That sounds as though he thinks that God says; 'right; no one is worthy of my love; they're all wicked. So I'm going to send a load of pain and suffering to make them turn towards me and ask me for help. Then, when they've repented and been made better people by suffering, THEN they'll be worthy of my love.'
Christ died for sinners - for wicked, godless and God hating people.
No one is worthy of God's love, and no one can ever make themselves worthy. If we could, salvation, and God's love, would be something we had earned for ourselves. It's not; that's what grace is. The wages of sin is death, Romans 6:23, and that's what we deserve - separation from God, spiritual death. But God in his mercy and grace sent his Son to lay down his life for us, John 10:11 and die for our sins, Matthew 26:28.
I agree that happiness - material blessing and physical prosperity - is not God's sole purpose for us. He wants us to know his Son who came to reconcile the world to the Father, 2 Corinthians 5:18-19; John 6:40. And yes, he may well speak to people in suffering and pain, which are sent by the devil to try to turn people away from God.
That bit I agree with. But not the words that God wants us to be able
to be loved by him. He already loves everyone; that's why he sent Jesus to die.