Hi Chaval, I just thought I would share that I am having very similar problems to you and am working toward, but have not found yet, a solution. My blood tests indicate everything is supposedly OK, though my prolactin is on the high end of normal and my T is somewhat in the lower area of the range.
When girls are ready for sex I can see that they are always much more horny than me. I see them panting etc, just kind of in a different world where their consciousness seems to be very much more occupied by lust than my own is. It makes me feel weak and inadequate to see that I am so much less driven than them, and it also makes me feel a little like I am acting/being a bit of a fraud when I engage them in sex. It is very difficult for me to have orgasms and I basically prefer to not even think about sex because it is so depressing to be faced with how low my sexual “potency” is. So I sympathize with your situation greatly.
Some physical symptoms that I have are weak erections that require constant stimulation, except in the morning. I always wake up with very hard erections in the shaft of my penis. However, the glans of my penis is almost never really hard, even near orgasm.
Some sensory symptoms I have include a vague feeling of something being “missing” in what I am feeling during stimulation. Often times, I even get a faint “itching” in my penis, or at least glans. It is like if I stimulate less, then I feel nothing. However, if I stimulate more, I can get the itching rather than pleasurable sensation. I mention this because I suspect it may be very similar to what you describe as “burning”. It is a mildy unpleasant sensation rather than the pleasurable sensation that is “supposed” to be there.
I hope you will update with how your situation goes. I intend to update with mine. At the current time, I am going through a process of seeing what an endocrinologist suggests. If that does not work out, then my hopes will be in that this is all caused by stress or that it was caused by previously taking Accutane, and that there might be a cure to damage caused by Accutane.