I have already read a lot about piriformis syndrome because I know it is one of the possibilities. That is not my problem. My burning sensation is very specific and allocated in the butt, thighs and soles. Doesn't get better with rest or exercise or stretching. I can't avoid sitting, have to drive, travel in airplane (live in PR, an island), work in the office or go to movies.
Few times in my life because of exercise or tension, have experienced sciatica pains. Its very different and goes away with aspirin or Tylenol. My burning (like fire) does not run from hips to feet like sciatica and there's no electricity feeling.
Its burning! The only way to alleviate is with ice (no more heat!) or with freezing creams with menthol like Biofreeze or cool-gel Bengay. Eventually have to take off the pressure by turning myself face down in bed or take my feet off the bed or chaise, for soles. Standing up or seat on ice or move from one butt to the other reliving the pressure is the only thing that gives relief to the burn.
I went to the neurologist because my symptoms. Seems more like to be neuropathy even tough I'm not diabetic, nor have any vitamin deficiency, illness on injury.
Because it only happens when pressure is applied, I think it has something to do with circulation, since always have problems with leg circulation, that is why I told you about my veins.
Please take some more time to study some other possibilities...