Why have my boobs been sore for 3 weeks I am not pregnant my last period was on June 26th?

Even if. you're not pregnant, pain in the breasts is most often related to conditions associated with hormones. If you pain has been persistent for 2 weeks, you should see a physician who will get a complete history an perform a complete exam before determining if any testing needs to be done to see if anything more could be going on.
Painful boobs. Breast tissue is mainly fat. If you take a lot of caffeine it causes retention of fluid in the fatty tissue of the breast causing them to be tender and painful. .