Chest pain. Does the pain doesn't go?

I am 22 years old suffering from chest pains Started from 27th January 2022 i did my blood test and chest xray on 21st feb, did my 2d echo on 5th march., latest ecg on 17th March all the test came back normal but still the pain is not gone and it aggrevates during night when I sleep and the sternum pains 24 hrs , I am unable to understand the reason the pain accompanies eith headache, sweating (sometimes) stomach ache nasal pain, arm pain it scares me if I am having some major or my life is in danger, I consulted doctors they said nothing to worry but the pain doesn't go, I request you to help me here by 1. Why does the pain doesn't go? What causes it 2. The test i performed do they have a valid period which i cam take as an assurance 3. When Am i suppose to consider it as an emergency and rush I am underweight, i don't smoke i dont have diabeties or cholesterol issues Request you to guide me, thank you!