I'm really struggling with sitting on a chair for more than 8 hours a day. It's causing me some heavy lower and upper back pain, and on top of that, I'm experiencing shortness of breath pretty frequently. I've spoken to a few doctors, and they've suggested B12 for the back pain and some gastric tablets for the breathing issues, but I still haven't seen much improvement. I'm getting a bit worried. Do you have any advice on what else I could try or what might be going on?