My fiance is diabetic, has a thick pinkish brown smelly discharge, pain and discomfort in pelvic region and breast tenderness. she has switch from injection to the pill about 3 months ago, pregnancy test negative, what could it be?

Vaginal discharge: A "pinkish brown discharge with odor" may be due to a yeast (fungal) vaginitis, but the "pink, brown" component may be oxidized blood. Breast tenderness also may be from early pregnancy (home pregnancy tests are not always accurate). The oral bcp's can cause mild bleeding if not taken punctually. Obtain a serum HCG test for pregnancy, and see your gyn physician for an exam and culture.