I need to pee about 15 times a day?is this normal?

i never used to have to go this much, but i came out of hospital a year ago after snapping my arm and they gave me a lot of stuff to keep away the pain. since then i need to pee a lot more. i don't mind it in the day but at night i am like clockwork - go to bed at 10 and pee, finish watching tele and pee, wake up at 3 in the morning and pee then again at about 6. beore i shower ime at it again. my mum says it because i drink a lot of water but surely this isn't normal?