Hi, I hope this mess finds you well, there is nothing to worry about regarding your anxiety, and I hope you get better after advice from professionals. 1. Sitting and doing work is not a deal, but we need to do a properly tailored exercise program for your issues. 2. Switching your posture frequently won't cause any serious issues, but the pain you're getting mainly you need to take care of that through exercises. 3 & 4. I hope you doing well in your food habits, please be on the same track. The actual issue is Acute Non-Specific Lower Back pain that leads to Anxiety. Try to do exercise to get rid of the pain in your activity.
Next Steps
Try to visit Spine Rehab centre where only concentrate on Progressive Exercises.
Health Tips
Don't Go Multiple Opinion