Is this back issue serious?

I have pain in my lower right back. In certain sitting positions it is hard for me to get a full breath, it feels constricted. It feels uncomfortable to walk. It’s not a serious pain, more uncomfortable than anything but the pain is still there. When I sit straight, it hurts more than it does if I slouch. I have a small issue with my spine being bent weird, but the doctor said the spine issue isn’t something to worry about. Could it be because of the spine? or did I just possibly sleep weird? Thank you.
Quick Edit: This has been happening for a couple days.