Thanks for writing to HCM
Some females have irregular periods
some times and it shouldn't make you worried.
It is not dangerous at all, but certain conditions may be associated with it like stress,diet,PCOD, exercise,contraceptive pills
White discharge should be treated as it may be fungal infection
. You can try clotrimazole
tablets for vaginal use for 7 days at bed time.
For backache ,you can take analgesics and if symptoms persists further investigation like X-rays etc. should be taken.