In the past I developed a bad case of sciatic (sp)nerve in my left leg. After PT and other treatments, I discovered my"office chair" was the culprit. The plastic base for the seat cushioning had a sharp edge all around to hold the foam cushion and you could feel it through the cushion and upholstery. It was pressing on my leg every time I sat at the computer or sewing machine. So check if the cushion does cover and "cushion" the framework of the seat. If you can get an adjustable one for seat height, then you can raise and lower and thus relief your body. I find raising my seat to the highest level so my arms are level with or above the table height helps me sit up straight and relieves the back pain. Hope you get this solved soon so you can enjoy your quilting.