Most of the brothers in all families are always arguing over stupid things most of the time, because it is a bit annoying to live with the same person almost 24 hours a day.
But a brother is a brother, is the only person that shares his/her blood with you, and despite the years that you take with him/her and the fights you have, he/she is always going to be there with you.
It is normal for children of the same sex to tell everything to each other and share many things. Even if your brother/sister isn't your own sex and you can't share so many things, you must be proud to have him/her.
It's not worth when you get angry with him/her say you wished you were an only child, because you never know what you have until you lose it.
So I just have only to said that you always have to help your brother/sister, be nice to him/her, share your things with him/her, play with him/her if it is necessary, and enjoy your life with him/her.