Yes, that is how the pubertal development going to be. It generally follows a developmental sequence as explained in the following link: http://www.mgh.harvard.edu/children/adolescenthealth/articles/aa_puberty.aspx
In the development sequence the pubic hair comes first and arm pit hair and voice changes take place later.
If you Google for ' Puberty in Boys ' and read the section under Puberty in Wikipedia, you will get more details.
Normally, the puberty in boys start during 11 years to 14 years and mostly completes by 16 to 18 years. Facial hairs and body hairs continue to develop for many years after Puberty.
Sorry to learn that you have pain in nipples and it should go away after puberty.However if you feel more pain, I advise you to see a doctor.Do not feel shy of discussing such problems with your parents, your health comes first.
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