If you're not sure what that really is, Dulak says it's a compression or irritation of a sciatic nerve. They run from your lower back down through your butt and into each leg (see the graphic, below).

Dr Pimple Popper has dealt with many old bumps and lumps in her time, and patient James has had his back cysts for over 25 years. After a quarter of a century of suffering, there was only one ...