Brother's, many of us have experienced our nipples briefly become sore and swollen during puberty, as I did at 14. This is common and no sign of Gynecomastia, an increase in the amount of breast gland tissue in boys or men, rather a common occurrence in both men and women during puberty and in adulthood too. If you had or are experiencing this and not comfortable talking about it, these articles may help answer some of your questions. This is a temporary condition that should go away quickly.
I am posting this as one of our brothers and close friend of mine stated he is having an issue with this and is 18, so I researched and provided him with some solid advice, now I am sharing it with all of us here.