My back is really sore?

I am in good shape and never had any persistent physical problems throughout my life even though I have played a lot of sports and worked out a lot. Two days ago I had a good night sleep, got out of bed and ate some food before heading out. I noticed my back felt a little sore but not to a point where I paid attention to it. The next morning it feels really sore, but I am still able to move around just really slowly. It still hurts, and I know that it will get better as it feels like I just tweaked it.

The only other time it has felt this way is when I lifted too heavy on the bench press without warming up about 6 years ago. I am not sure why it is hurting now, and I just want to know what caused it so I can try to prevent it from happening again. Is it just the really bumpy road I was on that had me bouncing nonstop for hours, or did I perhaps land too hard when I got out of the truck after I woke up? I always use the three step system so I do not jump out of my truck, but maybe I just was too hard this time without realizing it?

The next time I am at my house I need to get my heat pad and back brace.

 

Yeah I thought that at first but I think it is more in the middle. I do not hold it.