Persistent Urethral Irritation & Pain: Causes & Relief

Question
I'm a 28 yr Male college grad.  I have this sting burn or painful feeling on the Lucuna Magna (1/2cm down urethra) and along the rim of Meatus on the right side. I've had this for 3 1/2 weeks. I've been told I don't have an STD or Herpes and prostatitis is ruled out (physician). It's not a wart. I was treated for NGU and UTI based on the symptoms but they never went away. ER said there's no infection internally with bladder or other organs.  It's bothersome when my penis rubs against my boxers because it feels like needles stabing my meatus. I'm taking medication for numbing the urethra and cipro but all having no pos. effect. I've read forums on this same issue and nobody seems to know what it is.  My question is: What could it be? Can it be treated?  Can you give me some direction so that I can further research the issue?  Please Help.

Answer
I assume there was no foreign body used.... and if you were treated with STD meds like azithromycin and doxicycline then any cultures won't be helpful.  I have seen people with chronic inflammation in this area from repeated masturbation/sex and have had some urologists suggest that a short course of prednisone (10 days or so) may help.......