Ive been having sporadic breast pain on my left breast for about 2 months. it gets better during and after my period but continues as a dull pinch sporadically throughout the month. dr. suspected cysts; ultrasound was clear. what could it be?

If you are not on oral combination contraceptives, fibrocystic breast disease (FCD) can occur with non-symmetrical effect on breast tissue, with one side more affected than the other. A negative ultrasound may rule out cystic masses of a certain size, but your symptoms subsiding "during and after" your period suggest FCD. Ask your gyn about oral combination bcp's to minimize estrogen stimulation.