The price we pay for having the ability to walk upright is that much of that pressure and shock absorption that used to be distributed among our limbs when we walked on all fours is now transferred to our lower backs. But since we're sort of content with our two-legged mode of transportation (and willing to trade off wear and tear on our knuckles for an erect spine), we have to train our lower backs to deal with it.
Of the numerous risk factors for back pain (including smoking, your job, age, and certain diseases like arthritis), omental obesity (obesity around your abdominal tissues and organs) and core muscle weakness are the biggest. With obesity, it just makes anatomical sense: The bigger your belly, the more likely it is that your center of gravity is pulled forward, putting excess strain on your back. The solution's simple (at least in principle): Drop the weight, and you'll ease the tension.
On rare occasions, back pain is associated with tumors and infection, so it is wise - especially with back pain that doesn't go away after a few weeks of trying recommended drugs and diet treatments - to have doctors do a complete diagnosis to see if they can indeed pinpoint an atypical cause.
Find out more about this book:You: Being Beautiful - The Owner's Manual to Inner and Outer Beauty