Suggest treatment for painful urination

my 6 yr old boy started having painful urination today. He saw doc and did a urine test. Won't have results until tomorrow. This evening during his bath, his penis started burning again and I tried to get him to pee while in the bath. He was too scared to because of the pain/burning. I encouraged him and he tried but nothing would come out. He was trying so hard to pee that his tummy started hurting. It hurt so bad he started crying....and he never cries, so I know it must have been feeling so bad. I know it could possibly be soap becuase he likes to get that bad boy pretty clean with soap. Hm, I guess it is probably not about how clean it is more than how great it feels to wash it. :) but it has never happened before. Not sure what to do to help him w the pain.