Hello! thank you for your query, The most common cause of missed menses is pregnancy. First of all, before you take any medications make sure to rule out pregnancy first if you had any contact with your partner. If you have a regular cycle and this is the first time you missed your period then I advise taking a pregnancy test. Other causes of missed menses include hormonal imbalances and stress. Regarding your
low back pain, it may only be a muscular, but if your low back pain is accompanied by fever, difficulty urinating, you may do a urinalysis(urine exam) and Kidney Ureter Bladder
ultrasound as these may indicate a kidney problem or
urinary tract infection. Also, if there is an accompanied unusual
vaginal discharge along with fever it may also be due to a
pelvic inflammatory disease problem. Please check with your
medical doctor for further assessment and evaluation if the pain continues.
Meanwhile, I advise you to put hot water bag on the affected area for 15 minutes 2-3x a day, have plenty of rest and drink lots of water. If pregnancy is ruled out, then you can take any painreliever such as
mefenamic acid 500mg 3x a day or ibuprofen 200mg every 6 hours for pain.
I hope this helps, a feedback is greatly appreciated.
Thank you!