I have been having some problems with my butt.

It itches SEVERELY and even from time to time will begin to burn. It seems to be worse at times as compared to others, but exercise always seems to make it worse.

I've been dealing with this for months now, and it's starting to take a toll on my life. As a distance runner, I do not want to run for fear of aggravating this and having to be in discomfort for the rest of the day. Also, I've been eating less so I wont have to poop as much, because pooping always makes it worse as well.

I've noticed a few things:
A yellowish residue will sometimes appear when I wipe
There is hair from my butt coming off when I wipe

I went to see my family doctor who wrote it off as chaffage and sent me on my way with anti-chafe cream. It would sometimes relieve the pain but ultimately was unsuccessful.

Do you know what this could be and how I can fix it?? It's driving me insane..