Apart from the cold or flu, an aching back is the most common reason people visit their doctor. But the good news is that treatment for back pain is most often successful. Back injuries can be caused by a variety of factors. Low-back pain can stem from a variety of areas. A number of muscle groups surround the surface and deep layers of back and a pull or strain in one of these muscles can lead to back aches.
Back discs can also be a factor.
Discs are composed of a thick gelatinous substance surrounded by a tough outer ring. Sometimes the inner substance of a disc can penetrate through a tear of the outer ring and hit a nerve root, causing leg pain. This is called a herniation. Juhn notes that a herniation is different from a disc bulge, which can be common even in people without back pain. Back pain can also result from injury to the sciatic nerve, which runs from the buttocks down to the back of the leg.