Im a female and after masturbation my cum is brown, is that normal? there is also a little bit of pink/red, which i think might be blood.

See below. : Though likely nothing serious, your description suggests that there may be "something" bleeding from within the vaginal area with the brownish color possibly representing "old" blood and "pink/red" color more indicative of new, fresh bleeding. Would highly recommend a thorough and proper gynecological and pelvic exam for proper diagnosis.