I took the foundation class 3 weeks ago and it was wonderful. I used the chair in class and my back felt great. As I needed a new desk chair at home I bought one and have been using daily. However, I hate to say it is causing pain in my back in the area that the Stretchsit® nubs come in contact with my back. I also have the Stretchsit® Cushion in my car and it does not cause this problem. In looking at the nubs on both the chair & cushion, I have noticed that the Chair nubs are harder and pointed, while the nubs on the cushion are very clearly softer and flatter to the back, causing no direct pain in the area that it supports and comes in contact with. I also did not have trouble at all with the chair (same size I bought), while in class for 3 days. I believe I'm sitting in it properly and wondering if the chairs in class, since used over time, have softened the nubs, thus, not causing the same pain. I am wondering if there are any thoughts about this as I would hate to have to return the chair because I do believe it is allowing me to sit properly while at the computer, as well as keeping my spine elongated and in alignment.