Hello, Has anything come out of your belly button? if clear or see through fluid similar to spit or urine has come out, it can be a cyst remnant from birth that has become infected. If purulent material could be an infection, if there is a bulge it could be a hernia. Sometimes our belly buttons harbor bacteria because we do not clean it well. Since you have been using peroxide for a few days, avoid this and just clean gently with soapy water and wash cloth or qtip. let it attempt to heal, if your pain persists, consider seeking medical attention and requesting abdominal ultrasound of the area.