Replying to Pain in left side of lower back

Alright since i started skiing this season I started getting a pain on the left side of my back like right above my but but below my kidney. Its lasted for around 3 weeks now and I cant ski park because of it. Any quick twisting motion or drop makes it hurt alot. I was going to go to the doctor a week or 2 ago but thought it would get better so i didnt so im going this week. I really dont want to stop skiing a while just because of this stupid pain that came from nowhere. If anyone had something similiar please tell me thanks. +k