Should i get a mammogram i'm 27 and i been having pain in one of my breast and its usually off and on but it goes away but lately it hurts more?

Depends: If there is a lump present then definitely yes. In no mass and the pain is associated with your period, then most likely hormonakl.

Yes: At your age it is usually not cancer, rather hormonal imbalances but better safe than sorry, especially if you have a family history of breast cancer or other problems.

Probably not: Speak with your doctor. Generally ultrasound rather than mammography is the first imaging study of choice in your age group.