Not pregnant and not a nursing. i squeezed my nipples fluid came out. my i know the cause please?

Breast fluid: if the breast fluid was clear, just a drop when squeezed, and no other drainage, then that can occur normally with breast stimulation & manipulation. If the fluid was bloody or copious, see a MD and undergo testing(prolactin), examination, and if needed mammography. Prolactin is a hormone that can produce inappropriate breast secretions and can be treated by Rx.