What Causes Burning Sensation And Pressure During Urination?

I am 21 years old and masturbating since 4 years, I used to have alcohol but soon left it. Now when I masturbate once in a fortnight I have this burning sensation and a very high urge to pee with little pain in naval region. I also experience bowel movement. It lasts for a half an hour or so, please help me get out of this problem.