I understand the point about tendons and ligaments being lax or injured, and how they sometimes can be the cause of painful muscle spasms. However keep in mind that muscle spasms are not always due to an injury, nor are they always caused by tendon/ligament laxity. How many times have you had a stiff neck due to a trapezuis muscle spasm which can sometimes last all day long or in some cases even a few days? And I've also had painful cramping in my feet, calves, and even in my Lat muscles, which for me are all usually cured and prevented with daily stretching, along with adequate water, Taurine, and magnesium intake. I do understand though how the lower back area as well as the area along the entire spinal cord has a lot of things going on at a various times, with vertabrae, spinal cortex nerves, discs, as well as the musculature. But tight muscles often can be a contributing cause of pain as well as even a contributing cause of injury.
I think that most BBers in general severely neglect stretching, and the sad thing is, that the larger and thicker the muscles become, the greater the need is for them to be stretched on a daily basis. If you don't believe that, then ask yourself why it is that most women in general have more flexibility than men do: it's due to their muscles being thinner and smaller than men's are. It's as if you have two rubber bands...a very thick/wide one, and a very thin/narrow one. Which rubber band will be easier to stretch? Which one will be more flexible? Think of your muscles as those rubber bands. The thicker they are, the tighter they will tend to be, and that extra tightness has a greater requirement for the muscles to be stretched on a routine basis.