I have autism/Aspergers, so I carry with me the "apparent lack of empathy"
The book "How to win friends and influence people", by Dale Carnegie, was a God send to me, it it might help you learn how to cope with your NPD. To sum up the key points:
- Become genuinely interested in other people.
- Smile.
- Remember that a person's name is to that person the sweetest and most important sound in any language.
- Be a good listener. ...
- Talk in terms of the other person's interests.
- Make the other person feel important – and do it sincerely.
Make these a rules a part of your habits and you will have a far easier time in work.
Buy the book, read it cover to cover
And, get professional help, as needed.