Pain inside penis/urethra. did urinalysis and it says everything is normal. he said if the pain persist, come back for testing. what could this be?

Penile pain: Since your doctor has reassured you, probably you hae nothing harmful. Not all pain means disease. But if the problem continues, follow your doctor's advice and return for further evaluation. Depending on the nature and location of the pain, the next step might be referral to a urologist for urethroscopy -- i.e. to insert a scope and look for internal strictures, sores, etc.