I'm sexually active with my boyfriend i do not use any form of contraception, i have this brown discharge and pain, what is the discharge ?

Infection is tops : On my list of possibilities. Unprotected sex makes you vulnerable to a long list of infectious agents. And are you trying to get pregnant? You need a gynecological exam for possible infection and then possibly a discussion of birth control.

Probable infection: As a preventive measure it is recommended to use condoms Your vaginal discharge associated with pain are probably caused by bacterial vaginosis or an STD, depending of the causal agent you and your sexual partner should receive medical attention. I recommend you to go to your internal medicine or Gyn doctor for examination.

See details: Brown discharge and pain are most commonly associated with infection and/or abnormal uterine bleeding. I would need a lot more information to narrow down the possibilities. If this is a relatively new partner, sexually transmitted infections can be common. You need to be seen by a gynecologist. An exam with appropriate testing is required.