How chlamydia & gonnorhea cause epdidmytis or epididymo-orchitis? like if the cause is std means i am std positive for chlamydia & gonnorhea?

Not all epididymitis is due to gonorrhea or chlamydia. They are the most common causes at your age. Just having epididymitis doesn't mean you have these or any other STD. However, at your age nobody should ever be treated for epididymitis without first testing for gonorrhea and chlamydia (but not if the person has never been sexually active). Most cases should be treated with antibiotics...