Your breast became extra sensitive ?

Extra Sensitive Breast

Your breasts play an important role in childbirth. They are naturally sensitive and become far more so when pregnant. 
This is one of the most obvious early symptoms of pregnancy. 
When you become pregnant, your body begins preparing your breasts for producing milk and breastfeeding. 

Hormones start increasing. In addition to breast tenderness and swelling,
 your nipples may feel sore or extra sensitive. Some women notice their nipples darken in color. 
These symptoms are due to increasing amount of hCG hormone that begins at implantation . You may notice this pregnancy sign at bedtime when exercising or showering.