###Human: Why is there a dull aching pain above the back of my knee and buttock? ###Assistant: Hello. You lie down on your back, stretch your legs straigh, then lift your left lower limb up without bending knee joint. If you get severe pulling pain from buttock to whole leg, then it is sciatica. This test is called (SLR) straight leg raising test. Hamstring muscle pain in the back of the thigh and lower buttock when walking, straightening the leg, or bending over. Do the SLR test to know there is sciatica or not.