Is the pope infallible in everything he says?

No. Papal infallibility is a precisely defined, limited charism. The pope speaks infallibly only when he defines, ex cathedra, a doctrine of faith or morals to be held by the whole Church. His ordinary speeches, interviews, pastoral letters, and personal opinions do not carry this guarantee.

The Conditions for an Infallible Definition

The Catechism treats this charism as a gift given not to the pope personally but to the Church, so that the People of God may adhere without error to the faith once delivered to the saints (CCC 891).