Hello,
it sounds like you might have a scoliosis. or it could just be that your back is very rounded and so you notice your spine when you bend forward (kyphotic)
almost every one has a scoliosis to some degree. a scoliosis is an s-shaped curve of the spine in a side ways plane. the degree of the side ways curves makes it more or less noticable, more scoliotic, highly visible, less scoliotic barely visible.
as you have no pain i would not worry as this shows your spine has adapted well and is functioning just fine. if you start to get problems then you shouyld see some one to find out why you have pain and not just instantly blame it on a scoliosis.
have a good new year and stay healthy.