Can you help me identify the rash on my...?

It sounds like it could be fungal in nature. Have you tried powders or creams from over the counter that are for jock itch. They may work very well. That is my best suggestion from personal experience with my husband. Otherwise, I would recommend you go to a dermatologist you are comfortable with as it may be a dermatitis of some sort. I have sensitive skin and always get weird breakouts all over, so I am just giving you my best guess. Best of luck in curing this problem. BTW, your pictures are not viewable. I am only going off what you described.