Oh my god!
I've had the very same issue since mid 2000. I saw doctor after doctor and none of them could find anything. I was diagnosed with type 1 diabetes a year ago. I went on insulin injections but I couldn't get my dosages correct (Niether could my diabetic experts) Slowly my sugars returned to normal (between 4 & 8 mmol's) I've been off insulin for 8 months now because this isn't JUST diabetes (if at all) Anyway, I was found to have a 2+ candida overgrowth and a Blastocystis Hominis parasitic infection in my GI tract. This has lead to leaky gut syndrome, chronic fatigue and a host of nagging sysmptoms (that I've actually had for years) My Naturopath has been a major help in my recovery. The pain above, or just behind, the testicle has eased a little (Nothing to get too excited about yet) however, among other symptoms I've had a groin rash for 6 years, and this is starting to dissipate. Things are happening slowly but I'm fairly convinced we will nail it eventually.
I know the feeling mate, it's like you've been kicked in the cags constantly huh?