okay well i have the smaller set of Yamaha tenors at my school. we started to use the vest carriers, and before they caused me back pain, then i got used to it. now recently the pain is coming back...it starts to hurt real bad, but i did lower the j-bars a bit. would that have caused it to create more pain?

The carrier in your avatar picture is not a vest. It would cause pain in the back and shoulders. A true vest carrier has never caused me backpain, but rather abdominal strain.

Is the carrier in your picture the one you are using?

Lowering the J-bars shouldn't really have changed anything. Sounds like you need to just wear it more and more. I don't suggest a back-brace. That will most likely just make you rely on it as a crutch.

no we switched from those because those got in the way of our legs...it never bothered me when we used to wear them and now its dtarting to hurt again. i cant tell whats wrong

Lowering the J bars is what has caused the return of the pain. By lowering the bars you are moving the weight of the drums farther away from your center of gravity, which causes a greater force to be applied to your back. In structural engineering terms, this force is called a moment. The moment is causing a greater lateral (back to front) pressure on your spine which your body is not used to.

The problem is exacerbated by the fact that the switch to the vest carriers also changes the location of the pressure on your stomach. The vest carrier is not as long as the T-bar was, so the force that counteracts the rotational force by the moment is being applied higher on your torso than before.

In easy terms, it's the same thing as a seesaw. Have someone sit halfway to the end on one side while you are holding the opposite end down. If you move halfway to the center of your side you must apply more force than when you were on the end to keep them from hitting the ground. This is what happened when you switched to the vests from the T-bar. When you have them sit all the way at their end and you are still in the middle of your side, you will have to exert even more pressure than before. This is what happened when you lowered the J-bars.

So you have a choice:

Raise the J-bars back up or work on building your back muscle strength up.

Well Middle Age Man has an answer!!

If you are not allowed to raise the j-bars back up, then I would say to learn some back stretches. Do them before playing and after playing. If possible you should do them during your breaks. If back pain is experienced for a long period of time, in the future you most likely will have back problems. Doing stretches may prevent that from happening.