Can it be possible to produce breast milk without getting pregnant?

Yes but not normal: There are many concerns when a non pregnant individual produces breast milk including the possibilty of a brain tumor which is initially evaluated with blood tests. Even young neonates may occasionally produce milk from circulating maternal prolactin and on occasion women who undergo breast augmentation may briefly produce milk.Mhowever in the vast majority of cases this is not normal.

It is.: Endocrine disorders such as hyperprolactinemia can stimulate the milk production outside of pregnancy (galactorrhea). Many psychiatric and gastrointestinal drugs can also cause this symptom. See you physician asap if this is happening to you.