Sounds like sciatica. The sciatic nerve exits the spine at L5, S1 and travels all the way down the leg to the foot. Pressure on the nerve can be caused by degenerative disc or further down by tight piriformis muscles. I am recovering from suspected bulging L5, S1 disc and had excrutiatiing thigh pain, calf spasms and achey bum. They did the straight leg lift test where you lay flat and they lift your leg up to see if it causes pain, they then did the same with the good leg which caused pain in the bad leg and they used this to diagnose the disc problem rather than muscular... hope that helps.