I'm An 18 Year Old Female. For Years I Have

I'm an 18 year old female. For years I have had an issue where if I lie on a hard surface flat on my back, it's almost as if something in my back "sets" and it is sometimes difficult or even painful to get up. A year or two ago I began to notice that my lower spine was raised, right above my butt. It is centered and it is very visible. Within the past few months I have noticed it is becoming more visible. I'm curious if this could be a major/minor spinal issue, a growth or something I may not need to worry about. Thank you