Thank you Tulip for taking the time to respond thoroughly. I have had the chiropractor thing in the back of my mind but I haven't brought myself to get there yet. I know that this is ignorance on my part but I am scared to go for fear of the sales type pitches I hear my friends say they get when going there.
I thought it was something to do with my bike because i rode a different bike when we rented them while in Nevada. I now have it in my head that its MY bike that is causing the pain (while biking) and that I need the other bike.
I love to mountain bike but it seems as if the first thing (or really the only thing) to hurt at the end of the first lap of our trail (4.5 miles) is my lower back. This usually happens at the end of the ride and it prevents me from enjoying the ride and it makes me want to stop long before the rest of my body. I guess I was so shocked that I rode a bike for three hours on rougher terrain than i'm used to and I had no back pain. In fact, it didn't even feel like "work" or like exercise. I should say that my current bike is not a full suspension bike and the one I rented was. Could that be it?
pardon my ignorance here on all of this - i'm new to the forum but I have learned a lot just from poking around in the threads!
Gary Fisher is the other man in my life!