As they say, the first step is recognizing that you have a problem. It's wonderfully adult of you to consider it. The cool thing is that you're going to find out that not only do you have this problem, you likely have more than just these issues. Because you've opened up with yourself, you have the awesome opportunity to be a lot better person.
Personally, I have issue with being myopic (focus to easily on a singular task) and somewhat asperger/autistic (hard time recognizing emotional cues). Like you, I've had trouble with interacting with people.
The first thing I can suggest is finding a few people with whom you can confide your position, are supportive with wanting to see you be a better person, and willing to give you guidance. THEN TRUST THEM when they say you've done something not so well. If you're in a relationship, hopefully your SO will be willing to help. At work, maybe your boss or colleague will be willing to observe you and help you on your journey.
There are four stages of dealing with things:
* unconscious incompetent - You have a problem and don't know you have one.
* conscious incompetent - You recognize you have a problem, but don't know how to solve it.
* unconscious competent - You make an effort and happen to do better, but you're uncertain what it was that made a difference.
* conscious competent - You consistently do better because you know what to do in situations.
Notice that in the last one, I didn't say that you _understand_ why what you did makes a difference. If you truly are a narcissist, it means that the social aspects of your mind are weakly wired. I am that way, so even today I have trouble recognizing cues. But, I'm honest with people about it. My friends and colleagues know this about me. I tell them, "Just FYI, I have a hard time picking up cues. Please, just be very direct with me because I really want to help and see people are happy." My myopic natural can also be a feature: I'm willing to dig down into problems and really understand why something isn't working right. It doesn't bother me to laser focus on a difficult problem. Long ago I was taught that every personality trait can be positive or negative depending on how it is used. Learn how to be better and use what you can do for better things.
Finally, find a _good_ therapist. A good one will be interested in you and want to help you find out who you are and what you can be. A good one will ask a questions of you, but they will be questions you likely have never asked about yourself and should have answers.
You're on the right track.