You can be reassured that most painful spots don't turn out to be a cancer, however that is not a guarantee. The negative mammogram
, assuming that it was within the last six months to a year, is also very reassuring. However, the only way to know for sure is to ask your doctor to do do a small biopsy
of the lesion to see what it is. sometimes your doctor may even be able to tell by just looking at it. So please see your doctor for an exam.
I hope this helps, please let me know if you have any more questions.