I am 20 years old and for the last month to month and a half, I have been experiencing severe breast pain, especially at night. I am not overweight, pregnant (took a pregnancy test that came back negative), or have large breasts (Cup size B at 94 lbs, 5'4"). It seems to worsen at night. It becomes so painful, it wakes me up in my sleep. It is very sharp, achy pain--in my right breast. It goes on throughout the entire day but worsens at night. I have been on the same birth control for over a year, and never missed a dose, or have had problems. What could be causing this severe pain?