What Causes Pain At The Tip Of My Penis And Burning While Urinating?

I have had pain at the tip of my penis for about 5 days now, and burning while urinating. I feel like there is a constant dribbling of urine as if I haven t emptied my bladder. I am uncircumcised and it causes burning of the foreskin after a while of this happening. The pain is on the outside of my glans and it seems to come about every time it rubs on my boxers. I have been diagnosed with an enlarged prostate and have always had some dribbling, but this is more than I remember. Or maybe I m just hyperaware of it. I m worried about an infection because I had sex with my wife the day before this started. She s 9 months pregnant. Please advise.