I have written you previously about your back pain. Shipwreck's joke about bending forward is likely more accurate than "stress" as the reason for your back pain. Tell me, if your elbow hurt to move it in certain ways, would you blame it on stress? Why blame back pain on stress? Did it hurt to bend forward? Were you stiff when trying to stand after sitting for a prolonged period? Did certain activities aggravate your pain? If so, why do you blame your pain on mental stress and not mechanical stress?
The problem is typically prolonged mechanical loading can be a reason for the stress and it is cumulative - guess when this occurs prolonged postures, typically sitting. We do not view this as a mechanism of injury because it doesn't seem like it would hurt anything, but it can.
If your back pain acts mechanically - if it hurt to do certain things and felt better to do other things, it is unlikely that your pain is due to mental stress.
I implore you to rethink your idea about back pain and explore it. How about this, bend forward and touch your toes 10 times every 1-2 waking hours throughout the day. If this has an effect on your pain, it is not due to mental stress, but mechanical stress. If you try it, I think you will find something. If nothing changes, then I will concede that your pain does not appear to be mechanical. Please read more about the natural history of low back pain - it is typically self limiting, but this doesn't mean that it is due to mental stress.