Back pain has many causes including menstruation, heavy lifting or bad posture(the way you sit/stand).It can also be a symptom of a Sexually Transmitted Infection (STI).Get tested at a clinic IMMEDIATELY-untreated STIs can cause serious illness and infertility. ALL your sex partners must be treated or you will get infected with the STI again. Use condoms or abstain to prevent STIs.
Attribution: Straight Talk Foundation & Marie Stopes