Red:
I believe what you have is indeed localized, or site-specific as you call it, but that it is not a fungus or infection. Bacteria upstream in the bladder might cause frequency of urination but not sensitivity at the end of the stream only. Also, this would get worse over time, or else go away and stay away, not come and go.
I think you have a ombined physical/psychological problem. The orgonal inflammation left you with a reisdual sensitivity in an already sensitive area, as well as a predisposition to think about that part of the skin. When men think they are losing their hair, they complain that the scalp burns. Other examples, in my experience, are legion.
The first task is to eliminate a tretabale condition, such as an infection. You have done this. The next step is to convince yourself that this has indeed been done. If you're not convinced, get asd many opinions as it takes to do so. Then stop the hydrocortsione, stop all treatments, stop thinking about the area, and just get on with things.
If you follow this course, you may well find that the symptoms will gradually extinguish themselves over a period of weeks. Try it. What have you got to lose?
Good luck.
Dr. Rockoff