A weird problem with backbone when sitting , caused by HypoT?

[Guest guest]

I have always a weird problem which seems not important because it is not disturbing for my daily life.But I am really confused and doubt if it is related to any auto-immune diseases---more than ten years ago, I found that my backbone can not straight up when I am sitting (Absolutely others don't have this problem, and when I was a child, I didn't have it, neither. ) My backbone does not hurt, nor I feel painful. Precisely speaking, it is "weak" so that it could not stay straight up but remains "bending"/"curve" when I am sitting because it can not support the force of balance.I have a cousin who is a ankylosing spondylitis sufferer, and is it possible that I am affected by that related family heritage of auto-immune disease? I am diagnosed with Hashimoto's. Could it be caused by Hypothyroidism?Thanks