Hi
Welcome to health care magic and thanks for query.
Your age must be around 20-25 years .
Bleeding is off and on , scanty bleeding ,heavy bleeding i.e. irregular bleeding .
Clot and mild pain in back also associated .
Such type of symptoms in young female may be due to these possibilities , these are:
1 Poly Cystic
Ovarian Disease or
PCOS .Diagnosis can be confirmed by MRI or
ultrasound of bot ovaries .
2
Hormonal imbalance , diagnosis cab confirmed by blood examination for hormones.
3 Some local pathology in
uterus ( rarely ).
So consult a gynaecologist and get his opinion.
Hope this information will be useful for you .
Further , is any question I will reply happily.
Good luck.