Back Pain

I've been having a really hard time lately with exercising because I've had a ton of lower back pain. Most of the time when I stand up after sitting for any length of time, my tailbone hurts like crazy. I've always had a bad back, so this is nothing new, but it's worse than ever before. I'm not sure if it's the position on the recumbent bike or what. I might need to start looking on the internet for ideas on exercises that will either help me strengthen my back, or that are more gentle on the back.