If something is bothering me so much that, that's all I can think about. Should I talk to the person who is the caused of the problem?

I try to talk to them about it but they would ignore me. then later on I try again they said something that hurt. 4 days later they apologize and said they were ready to talk, but I was still hurt and I ignore them to keep myself calm. I messaged them apologizing for ignoring them and why, and if we can talk about it. Now they are ignoring me, I really need to talk to them and put everything in the past and work on our relationship. I don't understand why they are ignoring me, when I didn't cause this problems.

thanks for anyone answering.

You talk of "the person" who caused the problem.

Then you start using the plural pronoun "they" to say "they" are ignoring you.

So the only general advice I can give you is to give things a few days to settle down and see what happens.

Generally, no one can hurt you unless you allow them to.  Of course, in close relationships is is normal to be more vulnerable to what the other person is doing, but iit's hard to maintain a relationship if you are constantly being hurt by the other person.

You should always try and resolve any differences that you encounter with someone else.

If they apologize and you're not ready to hear it, you could say, "Thank you for your apology. I appreciate it. Please understand that I'm not ready to talk this through with you yet. Perhaps we could talk in a few days."

This way, you are acknowledging their apology and letting them know that you need a little time to process it.  Simply ignoring them doesn't help. Let them know what's going on in your head - you need a little time to process the event and then their subsequent apology.