Welcome to HCM,
You are having Fibrocystic disease
og breast, in which lumps are present and they can be painful or tender this discomfort may change with changes in hormone level during periods.
These are non cancerous in nature so please do not worry.
You have already done mammography
, and they also support your diagnosis.
You should be examined by a Surgeon who can palpate typical cobble stone type in upper and outer quadrant.
If there are any suspicious lump then only a fine needle biopsy or nipple fluid aspitration is done to rule out malignant lesion.
Risk of cancer is there but very small fraction, only thing sometime it may be difficult to diagnose in presence of fibrocystic disease.
For pain local or systemic analgesic
may be used and treatment option are few but may be dopamine agonist