I'm experiencing sudden onset, terrible pain after having suffered from occasional lower back pain. What could be causing this?
This is obviously something you should see a doctor about. If you have any type of really severe pain or if you have less severe pain that becomes chronic then it's time to see a doctor. The problem with low back pain is that so many different things can cause it from pulled muscles, to herniated discs, to nerve problems, to kidney or bladder problems, etc. It's always best to get in early and find out what's going on.
Some especially troubling symptoms in combination with low back pain include numbness or tingling in the legs or groin area, leg weakness and difficulty urinating. If you have any of these then get to the doctor as soon as you can.
Here's some more information on back pain. Good luck!
Sciatica – An Overview
Disc Herniation: What is It?
Back Pain and Sciatica