My wife’s was helped greatly by doing 20 minutes of slow stretching (to a Yoga video in her case) each morning.
I agree with dinoparty. I have piriformis syndrome, complicated by the fact that my sciatic nerve goes right through that muscle. When the sciatic nerve gets irritated, the pain shoots down my leg to the ankle. The orthopedic doctor gave me these stretching exercises, which really helps. For pain, I take generic ibuprofin.