I am 24, not married, having pain in breast from 4-5 days and my period time is also near. what is the cause?

Breast pain ...: ...Common near menses. If it persists or you feel a mass, see your gyn.

Premenstrual: As you describe, the breast pain is occurring prior to your period. If you have noticed this to be a pattern on the last few months, would be considered cyclic. Cyclic breast pain before periods is very common. It is caused by hormonal changes. The hormones related to the menstrual cycle and ovulation also stimulate the glands in the breasts which is painful for many women.