After ejaculation penis burns until i have an antibiotic.

Iam 28yr old male.At the age of 22 I had UTI,penis used to burn like
anything after masturbation.I have gone for lots of tests and everythig
was normal.I never had sex.I have used many antibiotics like
norflox,ciproflaxin.One urologist suggested for Semen culture and
steptococci was found.Then it was sensitive for tetracycleine.I used
for 1 week and everything was gone.

Now after 4 years iam facing the same problem.Agagin urologist
suggested for Semen culture and Ecoli was found.It was sensitive to CEFTUM.I used it but the pain still exists.As long as i use the antibiotic it is fine.if i stop and masterbate then pain starts agagin.
urine tests show normal.had ultrasound scan of abdomen and prostarte
was normal.iam currently usinng BACTRIUM.But the same problem exists.I dont have any other probs in body,neither fecer nor weakness.
What could be the root cause of the problem.is it prostatitis or some
damage in urethra.Kindly suggest

pain exists till i take an antibiotic.if i masturbate it starts agagin.......

You know the old saying "doctor it hurts when I do this." The doctor says "then don't do that!" I suggest you get a girlfreind; I also think you have inserted, or are inserting, something into your urinary tract and have damaged it. Quit masturbaring for a few weeks and leave yourself alone. Then, grow up and find a mate.