I have the same burning like its on fire starting around my tail bone and it goes down my left leg it also goes numb i have scoliosis in my lower back and i think its got to be a pinched nerve...That could be whats wrong i know it sucks it really hard to sleep because of it
Everything is a symptom for cancer. ;D
If you're really worried do a followup.
Western medicine isn't my specialty but if you want to take it from a crackpot like me we can try applying pressure to a few meridian points. You mention pain groin and numbness so that makes me think that the problem may be in the Kidneys(the points for both run close together)
Place your finger below your collar bone and around three inches away from your center-line and press down for around 4-5 seconds(you should feel some dull pain from the pressure)
work you way down around an inch at a time but staying the same distance from the center-line. After you have crossed around 6 points move your finger down to the upper abdomen. This time I want you to do the same thing but only an inch away from your center-line. Do this for about 11 inches.
Now do the same thing to the space in the bottom-rear corner of your knee.(The side closer to your center-line)
About halfway down the side of your inner calve do it there too.
Work down maybe 2 inches and use two fingers instead of 1.
Apply pressure just about everywhere around the ridge of the inner 'bump' of your ankle.
Finally apply pressure about an inch forward of the center of your foot's arch.
Repeat this on the opposite side of your body, if any part of it sooths the pain then focus on that point and ignore the rest.
Alternatively the points for directly addressing problems in the groin are along the groin itself(you could just apply the inch apart logic here)
You could try both and see if it works for you, but I'd recommend getting a followup in case it really is something serious, and I don't know any pressure points for curing cancer. Better safe than sorry.