Abdomen pain started after around three months i started to drink a huge amount of water around 4/5 l per day with frequent urine pass.why is this ?

Frequent urination: If you are drinking 4-5 liters of fluid a day, your kidneys are doing their job of excreting excess water. I suspect that your urine is quite light in color. If you drink, only two liters of fluids/day, your urine production should decrease. If not, see a doctor as your kidneys may be diseased or you have one that is causing this increased amount of urine.