What Causes Pain In Thigh Muscle?

I have sciatica, lumbar spinal stenosis, a ruptured disk, and degenerative disk disease. Coughing hurts the thigh muscle just above the bend of the knee. Recent bronchitis has had me coughing so much that the muscle hurts nonstop all the way from the glutes to the knee. It's a deep burning pain with drawing cramps. It hurts to walk and I'm walking hunched over. Am I damaging the muscle or just overstimulating the sciatic nerve?