I doubt very much that you are a sociopath. The fact that you are concerned about being sociopathic is, ironically, an indication that you probably aren’t.
At 13, you are at the beginning of the teen years, a time when people figure out who they are and what they value — and when people often make decisions about what kind of person they want to be. Your letter shows you are a sensitive person who is considering big questions.
My guess is that it is a little scary to you to think about really understanding another person’s pain so you avoid it. My other guess is that you understand that behavior as a kid isn’t going to be helpful as you get older, but you aren’t sure how to go about changing a pattern of lying. These are exactly the kinds of issues you should be thinking about at this point in your life. You can decide how you want to use your natural sensitivity and what changes you want to make.
I’m sorry that you don’t think your friends could relate. Chances are that many of them are dealing with the same kinds of questions. Sadly everyone is thinking that no one else is grappling with the same stuff so no one shares and everyone feels like they are the only weird kid thinking about this stuff. Believe me, every teen struggles with it. It’s perfectly normal. I hope you will start to make some baby steps toward having heart-to-hearts with friends or maybe with adults you trust. You don’t have to figure this all out on your own.
I wish you well.