What kind of doctor i talk to about sexual problem.?

Depends: Your general doctor can be a good start. If male a urologist. If female your gynecologist. If your issue is more of an emotional/psychological basis a sex therapist may be the right person to see. If you can give more details in your question, more specific answer is possible.

See Below: Sexual problems are handled by general doctors (internal medicine or family practice), urologists, and gynecologists.