I just signed up with T Nation, so this is my first post here, just for you.
One possibility for your problem(s): Varicoceles.
You can get yourself checked for varicoceles through your urologist --- but get him to arrange an ultrasound with a good technician.
I'd also get a sperm analysis done.
I have bilateral varicoceles, which have caused extensive testicular atrophy, azoospermia, low T (~350ng/dL). There are a number of follow on health problems, but I'll save that info for another post. My LH and FSH numbers are through the roof.
Varicoceles are like varicose veins in your legs, except they are located in the veins coming from the testes. In my case they are not noticeable except by feel. They sometimes cause pain, such as when driving. Over time they lead to testicular atrophy, infertility, and low testosterone in some men (not all men, just the unlucky ones). Just google "varicocele" and you'll find lots of info.
In my case I probably had varicoceles since my 20s. At 30 I saw a urologist and he missed them. At 39 I saw another urologist and he missed them, as did the ultrasound technician who in retrospect was incompetent. This year at age 42 a third urologist also missed them, but luckily he did send me to a good ultrasound technician who had no problem finding the large (>4mm) varicoceles. So now I will be seeing the urologist again about my shrunken nuts, hoping for a surgery sooner rather than later.
PS: I'd also be interested in hearing your urologist's reasoning behind HcG.