Had urethral pain for 6 days but it went away. have had tingling in belly button and tip of penis for 3 days since the pain ended. what could this be?

Maybe nothing...: Possibly urethritis (i.e. an STD), but probably not unless you also had abnormal discharge of pus or mucus. And urethritis would not be likely to clear up so quickly without treatment. Or maybe you passed a stone? Or non-STD urinary tract infection (very rare at your age). If the symptoms do not return, probably nothing need be done. But see your doctor if pain returns or other symptoms show up.