thank you for posting your query in healthcaremagic.com.... see first of all, painful periods are not a very rare thing and many women experience pain abdomen and back during their periods...vaginal discharge too is not unnatural in many... so unless your interval and duration and amount of bleeding remains fine, you need not worry much about painful menstruation and take proper painkillers and that would be enough.... well the severe back pain may be due to the back injury you mentioned....so dont ignore that and visit your PHYSICIAN or an ORHTOPAEDICIAN for sure... he/she will thoroughly examine you and give their valuable advice.... hope this was helpful.... contact me for any further queries..... regards