I had a cold war with my boyfriend for many days, but I didn't find a message or a phone call. I sent him a message and didn't reply. I called him, but he didn't answer.

There are two possibilities. One is that your boyfriend is still angry. If he is angry, he will be fine. The other is more troublesome. He may want to break up with you, but he is currently hesitating or waiting for you to break up. You can go to his place of residence or work and ask him calmly why.