Hi. I can understand the plight you are going through. Gone through the history and findings. You have already taken the best possible treatment one would suggest - no doubt about it. Normal blood, urine and CT are normal. The symptom burning is according to me classical about the nerve related. You can re-consult the Urologist or take a second opinion of another Urologist and/ or Neurologist. We have to find the reason of it. There can be a nerve entrapment in muscles of abdomen ( might be a developing hernia), or along the course from the spine to the level of scrotum. I think a medicine like amitryptiline or gabapentin in an appropriate dose can definitely improve your symptoms and is diagnostic as well as therapeutic exercise. Local injection along the course of the nerve is also a diagnostic test. In old times we used to excise a part of the nerve ( neurectomy) when newer medicines were not available. Please do not worry - this is completely curable problem. Please give me the feed back about your diagnosis and treatment. Dr T Chandrakant.