A bright red, excruciating pain, lump on buttocks.

I'm not sure if this is the right area to put this topic in. So here i go.

There is a very bright red lump on my buttocks right near the butt hole that keeps spitting out yellow fluid, which i believe is Puss, and it never wants to heal. Its been going on for about 6+ months now. The lump has sealed before, however, puss keeps on building up within the new layer of skin that has grown over the lump, thus "wrinkling" that newly developed skin area and eventually erodes away and the lump is revealed again. This has happened 2 times to me already. It heals and then it comes back. I have tried putting alcohol on it, and it does eventually "seal" up after a week, and another week later, it pops open again. The pain is unimaginable, intensifying, and feels deadly when i walk, or sit down. Because of me walking, the lump is rubbed against my butt cheeks therefore causing the unbelievable pain.

The following links below contains graphical images.

This is a square piece of tissue role that was placed under the lump after sitting down on it for several hours.