Suggest Treatment For Severe Back Pain

I've been having bad back pain since i was 16 years old I am now 22 years old i started puberty early and have always had big breast so I'm assuming that's why I have horrible back pain. But ever since I've had my two children its gotten ridiculous. Surgery is not an option I can't afford it but I was wondering if there was something I could do to help ease the pain? The pain is mainly in my lower back and right in the middle of my shoulder blade