I had a pain but it went away?

Last night I had a very bad pain in my lower back and below my stomach and had the urge to pee but couldn't. Now it's the next day and I feel better then ever. My back feels great and so does my stomach. Im 12 years old and haven't gotten my period yet. And now im urinating normally. I was just wondering could this still be something else. I asked my mom and she said im probably getting ready for my period? Could this be true? Thank you for anybody to help me!