You have urethritis, i.e. an infection inside the penis. It is an STD. Quick onset (only 3 days) makes gonorrhea most likely, but it could be nongonococcal urethritis (NGU), mostly commonly due to chlamydia. Yes, it can be treated. You need to see a health care provider right away.
Good luck-- HHH, MD
ANd yes, it is likely to be infectious, so please don't have sex with anyone (even with condoms) until it has been successfully treated.
My pee does not sting but I have white discharge when I do pee sometimes can this be an STD, if so what kinda..My sexually partner his pee sometimes burns and he also has white discharge..What could this be..HELP!!!!