Hello, I Experience A Sharp Pain On My Lower Back

Hello, I experience a sharp pain on my lower back - right side - right above my buttock; it happens mostly when I bend down, when I come back up the pain is extremely sharp followed by a strange cracking/popping noise.
I've never cracked my back but I have heard it done and it doesn't sound like that, it sounds like two bones moving against one another (dull-like).