Skin problems on the penis

I wanted to ask if you could give me any suggestions or advice on what this might be. First of all, about 5 years ago I noticed a red plaque on the right side of my penis gland. I never really thought anything of it cause it didn't cause any discomfort or pain of any kind. It was just there. About a year and a half ago, one night after sex with my wife, it started to burn, tingle and itch really bad. The next couple days the pain was unbearable. Severe itching and burning to the point I made a doctors appointment. The doctor suggested it may be an std which I thought was impossible, I've only be with one woman in my whole life but they suggested I should be tested for all of the most common stds. So I went to the clinic was tested. I told the doctor there about why I thought I might have an std, I was examined and told that by the appearance of it, it was not an std but a yeast infection. They took cultures and blood and tested for stds anyways, results all came back negative. I was prescribed an anti fungal cream which helped clear it up some but did not make it go away, I've been back to the doctor 6 times, seen the urologist 2 times and all they keep telling me is it isn't an std but some kind of skin irritation. They gave me some cream to put on it, all it does is make the redness disappear for a while but as soon as I quit using it, it comes back. The pain is not nearly as bad as it was the first time but it itches and is sore all of the time. It gets twice as bad after sex for at least 3 days after. It appears as red skin with very small red bumps, itches and burns frequently. I have lived with this for almost 2 years now, it doesn't go away and nothing I try helps, could you please offer your advice on what it may be or what I should do. Thank you.

[Nate26]

I also forgot to mention that the very tip of my penis also is very irritated, it gets swollen and has a small white bump on it that comes and goes. Again it is the worse after any type of sexual activity. Please help, I'm a nervous wreak over this and its affecting my sex life.