Hi,
As the previous poster suggested, it could be that you are experiencing symptoms of a Urinary Tract Infection (UTI), which can produce the type of pain that you've described. If it continues for three days or more, please seek medical advice. Usually, antibiotics are given, along with pain meds to alleviate discomfort. They can also give you good guidance on supportive home treatment, too. Be sure and drink plenty of fluids, and go to the bathroom when you feel the need to.
It may also be worth getting this checked out medically, so as to rule out other potential issues.
I'd be a little cautious about cranberry juice. Some people find it helpful, but others (like myself) have been warned away from it, as it can be more of an irritant, rather than a help. I tend to stay well away from anything acidic and spicy while I'm symptomatic with something like this.
I hope that you feel better, soon!.