Hi!
You are probably dealing with a urinary tract infection. I felt the same belly button pain when I got my first urinary tract infection. I suggest you check with your doctor and have a urine analysis and a culture. You should also mention to your doctor the pain in the back, I suggest you also have an ultrasound of your bladder and kidneys, to check for any possible kidney stones as well.
Good luck! :)
I'm a newbie here and I'm not a doctor. I have a problem with my penis right now and I'm going to see my doctor next saturday. Well, I guess you may have a bladder infection. Wait until Miss Vanessa answer your question. Do yourself a favor and see a doctor as soon as possible.
Good luck.