One possible way to proceed might be to look into the practice of "insight meditation". Then, if you can establish an insight meditation practice, see if you can bring forth one feeling or emotional response to something in your past or in your present day-to-day life. Use this feeling as the object of your practice. Perhaps this practice will lead you to other feelings that you aren't even aware of at the present time. Then you can begin to use this new feeling or feelings in your practice as well. Clearly, it would be best if you could find an insight meditation teacher to work with you on this. But if not there are lots of books available on the subject. And I'm sure there are resources on the internet too.

I'm not familiar with such things as DBT or CBT. But perhaps these types of training programs may also be of help with this type of concern. Good luck!