HI. With the mammograph shoeing normal appearance still having pan and swelling indicate me of an abscess as the first probability and a rare thought about cancers ( usually is painless.). You need to start antibiotic and anti-inflammatory medicines at once under the guidance of a Doctor. Multiple FNAC and ultrasonography can indicate the cause. You have to undergo a proper clinical examination to be done by a Doctor who can catch many of the problems on your proper history and physical examination and can then guide for further investigations and treatment. Also undergo the blood tests to see that WBC count is normal or elevated, that you are not diabetic and have no other medical problems.