What condition am I suffering from?

I'm a 22 year old male and think that I may still have growing pains, or I just have some unexplained intermittent pain. The pain has been going on since I was about 16, and it stems from my lower back. When I was younger the pain would sometimes be excruciating to the point that I had to stay in bed, but it would only be for about 10 minutes at tops, and then it would go away and not come back in the same form or intensity for months on end. Sometimes the same pain would not reoccur for around 6-9 months. I'm wondering though, if this is really growing pains or something else, again the pain is strictly to my lower back and is very intermittent. Also physically I am in ok shape and not really allergic to anything.