After bending my back always feels stiff so that it takes me a few seconds to straighten up again?

Try daily walking. This sounds like a musculoskeletal related issue. Research has shown that daily walking alone can significantly improve this type of pain you are experiencing.
Add some stretching. Adding some stretching and careful back and abdominal exercises will help as well.
Degenerative joint d. You probably have degenerative joint disease of the back. Physical therapy will probably help.