Thanks for the query to H.C.M. Forum.
You are having amenorrhea
( no bleeding from 4 months) , presumed that previously there was regular menses .
Since you are very young so may be due to ,
1PCOD ( Poly Cystic Ovarian Disease
) , diagnosis can be confirmed by ultrasound
of both varies as in this age group this is the most common cause of amenorrhea.
2 Fibroid in the uterus , diagnosis can be confirmed by ultrasound of uterus .
3 Hormonal imbalance is the another cause in this age group . Diagnosis can be confirmed by blood examination for estrogen , androgen , F SH/ L H ratio.
In my opinion consult a gynecologist and get his opinion and treatment for menses . Vaginal itching
may be due to unhygienic condition so take care of personal hygiene . Use antiseptic soap for local wash with antifungal cream application.
Stomach pain is due to tension ( stress ) , for this you may need antacid , if symptoms are severe then take proton pump
So first of all consult gynecologist and get his opinion.
Good luck. Dr. HET