Good I Day! Im 21 Years Old, And I'm Asking

Good i day! Im 21 years old, and i'm asking about my condition. Im a 5th yr college student. When i was 1st year our school give a result of my chest xray that have a findings of ptb. I went to a doctor and said it was a tuberculosis after that she prescribe me to buy those medicines, i cant recall what was the medicine. After that i went to a health center in our place and said that why i take those medicines even if not testing my sputum and the basis only was my xray. After that testing sputum the resultis negative. And then after 2 years i already get another xray which the result is the same on what said earlier , i went to work in my free days and then i got my xray again and the result became the same as i expected. Is it possible that 5 years i have a findings like that which is a ptb.? Even if i dont even feel any symptoms of that sickness. I am worried why it is always the result of my xray?..