Thanks for your query.You have burning sensation in Urethra
,You have all the tests for sexually Transmitted diseases.Have you had a contact with unknown woman or prostitute?From your symptoms it looks like you have severe urethritis
.Pl take Tab Doxycyclin 100 mg twice daily for 3 weeks along with urinary antiseptics like Tab Niftran
100 mg twice daily.If your symptoms still persist pl consult Urologist
and get your uorthrogram done to rule out stricture of the urethra.