Hello dear
I understand your concern
Presence of period and negative pregnancy rule out the pregnancy cause.
Breast pain and nausea could be due to hormonal imbalance,
ovarian cyst, endomteriosis, acid reflux/
gastritis.
I would suggest to consult the gynecologist and undergo reproductive hormone analysis, routine blood tests, USG scan and
ovarian follicle study to confirm the cause.
Specific treatment depend on the cause.
Meanwhile take following advises:
Tablet meftal saps
Tablet rantac before meal
Do gentle massage to breast with evening prime rose oil
Avoid stress, drink plenty of water, eat healthy diet and do regular exercise.
Hope this may help you
Best regards
Dr. SAGAR