Suggest Remedy For Back Pain Post Falling Off From Horse

Hi, November last year (2014) I fell off my horse jumping and landed flat on my back, I got straight back on after the fall not thinking anything of it, but since then I've had a pain in my back. The pain isn't there all the time, only if I agrivate it by landing weirdly in the saddle after a jump or bending back too far, things like that. I was wearing a body protector when I fell. Should I be worried or should I ist give it time to rest?