I'm not sure specifically which 'main khayal hoon kisi aur ka' you are referring to. It could be a song, a poem, or something else. Without more context, it's difficult to tell the full story.
If it is a song, without listening to it or having more details about its lyrics and the context in which it was created, it's hard to give the full story. But generally, a song with such a title might be about unrequited love or a sense of self - effacement where the singer feels like they are just a thought in someone else's mind, maybe longing for that person to notice them.
Well, 'tu pyar hai kisi aur ka' implies that it's a love that is for someone else. In a school love story context, it could be about a person who has feelings for someone else in the school. Maybe it's a story of unrequited love, where the protagonist loves a classmate who doesn't feel the same way. It could also be a story full of jealousy and longing as the person watches their beloved be with others.
The main plot could be that of a heartbroken student. They discover that the person they like is in love with someone else. So they have to deal with the pain of seeing their crush with another person every day at school. They might struggle to move on and find themselves constantly comparing themselves to the other person their crush loves.
I'm sorry, I haven't read the 'kisi se kya bichar gaye novel' so I can't really say what it's about. Maybe it's about the relationship between characters or some kind of event that makes people wonder what others think.
It might be about a couple who are separated due to some misunderstandings, and then they try to find their way back to each other in the 'gum hai kisi ke pyar mein star plus story'. For example, one of them might have made a sacrifice for the other's happiness, but later they realize they can't live without each other.
One bhai behan ki hindi story could be about a brother and sister who lived in a small village. The brother was very protective of his sister. Once, when there was a drought, he walked long distances every day to fetch water for his sister and family. The sister, in turn, would help with household chores and also take care of their ailing parents. Their bond was so strong that they supported each other through all the hardships.
One interesting 'bhai behan ki hot story' could be that a brother and sister start a small business together. The brother has the business acumen and the sister has great creativity in product design. They combine their skills and launch a successful line of handmade crafts. Their relationship of trust and mutual respect helps them overcome any business hurdles.