I have problem of irregular period i want the permanent solution of this plz help me ?

When it was started it was irregular for 2 tn 3 years but was again normal sometime scanty bleeding was seen for 3 days and thenafter normal flow was and sometime bleeding was normal so i didnt consult to docter.since last two years it again becomes irregular i consulted to doctor he prescribed norethisterone @3 tab tid for 10 days and after period called to check up that time he gave same drug @1 tab od from 16 to 25 days of period for 3 month then after it was normally occuring for about 1.5 years but again the problem seen after i had bike accident at that time he said my uterus usg normal and for the problem of scanty bleeding he gave the same drug at samd dose for 3 month and it was normal so again the problem repeated i went to him again he gave as the prescription to follow for 6 month bt after that the problem was still the same so i went to next doctor 23 days ago she said my uterus usg is normal and gave Ovral-G @1 tab od for 3 month so now i am taking that drug but still no mens. I want to know its solution and my all health status is normal wt 51 kg ht 5'1 ft and pressure is 110 by 70.have have also seen website about PCOS and in my view i hav not any symptoms of it.and one thing that i have never experience severe abdominal pain just mild pain but i had considerable back pain.plz help me i am too much worried it does it need to worry about or wat should i do?r 3 month then after it was normally occuring for about 1.5 years but again the problem seen after i had bike accident at that time he said my uterus usg normal and for the problem of scanty bleeding he gave the same drug at samd dose for 3 month and it was normal so again the problem repeated i went to him again he gave as the prescription to follow for 6 month bt after that the problem was still the same so i went to next doctor 23 days ago she said my uterus usg is normal and gave Ovral-G @1 tab od for 3 month so now i am taking that drug but still no mens. I want to know its solution and my