When it really flares up, it is excruciating. I've been bedridden for several days twice. Ice in the first 24 hours, followed by heat thereafter, seems to help, along with ibuprofen. Stretching has helped me reduce the frequency of my episodes. One stretch that I didn't even consider until I went to physical therapy involves lying on the floor on your stomach and then using your arms to slowly push your torso up off the floor, while keeping your legs/pelvis on the floor. In my case, I didn't understand how this would help since it seemed my issue was caused by tight hamstrings, and this stretch was not stretching those tight muscles, but it did help.