How do you use "suffer" and "suffer from"?

Question

How do you use "suffer" and "suffer from"?
I am not sure.
please give me some example sentences.
Does they have a different meaning ?
and How do you choose them?
I am confused.

ps.
"suffer for"
when do you select this idiom?
Many thanks

Answer 1

I suffer.
i.e. I endure pain / deprivation

I shan't suffer your insolence
i.e. I will not tolerate your insolence.

he is suffering from smallpox.
i.e. smallpox is making him ill

I suffer for you.
i.e. I endure dire consequences to back you up, or,
you suffering makes me suffer.

Answer 2

Put the dog out of it's misery if you don't want it to suffer.
Those people suffer from lack of food.
Nobody wants to suffer for no reason

Answer 3

I sure dont want to suffer when I die.
Who ever stole my sterio I hope suffers for what they did.
They suffer from different medical problems.