Your degree of social interaction is your choice. Some people choose to live alone deep in a forest, others to live alone in the mountains. Some people choose isolation even while living in the middle of a large, congested city. The only important question is why they have made that choice. Was it for healthy reasons or unhealthy reasons? Healthy reasons would be comprised of factors that are not harmful to the individual, in the short-term or long-term, and are not harmful to others. Unhealthy reasons would include misconceptions, irrational thoughts, delusions, fears and phobias, etc.
If one were truly an introvert, social isolation would be the result of fear. Introverts are simply “shy.” Fear stops them from putting up their hand in class, from calling someone on the phone, making eye contact with someone they are attracted to, etc. Introverts do not prefer social isolation. They prefer not being shy.
You say that you had a perfectly normal childhood but can you be sure that that is really true? I hope you recognize that having an overly affectionate mother who smothered you with attention is not a perfectly normal childhood. Too little affection is a problem, smothering affection is also a problem.
You say that you do not feel much empathy when discussing things with other people. You say that you are not concerned with other people’s dreams or problems. You might be surprised to know that most people are not concerned with the dreams and problems of other people, even though they have learned to pretend as if they are. Their empathy and seeming concern is actually the result of learned social acting skills. You know how you feel on the inside when someone is discussing their dreams or problems and you know that you don’t care too much at all about what you are hearing. However, you don’t know what others are feeling on the inside when they are hearing someone discuss their dreams or problems. In most cases, it could well be that you are feeling exactly the same thing.
You don’t mention drug usage. Many drugs, legal or illegal, can affect and do affect the emotions you feel. My advice to you would be to find a good therapist and to discuss with that therapist the things that you have brought up and asked in your letter. The letter that you wrote was comprised of 333 words. That’s all the information that I have about you and that is not nearly enough to provide you with any significant, personal insight. Many, many thousands of words can be exchanged in one hour of counseling. I wish you the best of luck.