The main reason for distraction is that you are not interested in this matter, or there are other things that interest you more that attract your attention. This is normal and happens to everyone. No one can be highly focused all the time. Everyone will be distracted sometimes, but you just don't see it.
Why are some people able to concentrate highly, while others quickly "deserve"? This also depends on personal habits. Some people take everything very seriously since childhood, and such people can easily concentrate highly. Some people have not cared much about anything since childhood and have not paid much attention to their thoughts. Such people are prone to desertion. It's just a matter of attitude.
If you attach great importance to this matter but still get distracted, it is a matter of interest. It's hard to concentrate on something you're not interested in.
Khan, I used to be like this too, but then I got irritated and calmed down. It's quite difficult at first, just try it slowly. You can only work hard on your own, and you cannot expect that there will be a way to succeed immediately.
If you want to focus on something that you are not interested in, then you need to train slowly. You can bring a paper and pen and take notes while listening. Don't say irrelevant things to others at will during the process, as this will easily distract your attention. Follow the speaker with your eyes, don't look around, and be sure to take notes with your hands. This makes it easy to focus.
The same goes for books that you are not interested in but must read. It works, and that's what I've always done. You can try it.
Back to LZ: It is impossible to be highly focused all the time. If you feel that your attention is beginning to scatter, take a break, or change to other subjects. Gods can get distracted, let alone humans. If you really can't do it anymore and you are always worried about other things, then finish other things first and then continue studying. Complete what you want to do most. If you want to play, have fun for a while. When you are done having fun, you can concentrate on studying.