Elizabeth, unless the pain and warmth develops into something pretty dramatic - a swollen, red, painful, perhaps itchy breast - you've probably just got some hormonal issues going on. Breast cancer isn't usually signalled by pain or heaviness or tenderness. I'd wait and see if it disappears with your next period. And in the meantime, take a look at my current post on breast cancer symptoms - and why what you describe probably ISN'T a symptom. Good luck! - PJH