How to gain more weights from eating?

Patient: Hello – I’m 14 years old and I’m so thin. I really want to gain a few more weights, but there’s nothing I can do. I have tried eating different kind of food especially soups(!) but no results.I’m not weak nor sick. But I really want to gain more weights. Since I cannot exercise much and I’ve already tried eating many food but no results, I’m so upset about myself. What is wrong with me?? All of my friends are okay except me.Please help. What can I do to gain more weights and how can I maintain it??? Also, like I mentioned above, I cannot exercise much. Even I’m not so weak but I cannot exercise for a long time…Thanks.Reach.

Symptoms: I’m thin and I want to get more weights.