Back pain when you bend forward or when you sit? -This is the most common reason for back pain

Back pain in general is discussed in Back Pain

Do you have back pain bending forward? If your health care provider has excluded serious spinal problems, you can try an easy back exercise to improve your pain. Walking and stretching are the most important tools for back pain management. Not all exercises are helpful. Listen to your body. It is okay to be a bit uncomfortable at first, but if it hurts too much, stop and consult a profession.
Initially you may have to do the stretching exercise a bit more. Once your pain has improved, maintain your back with the exercise twice a day. You can initially also walk often for short distances, even if only for a few minutes, until your pain starts to improve.

If you have severe pain: You need to start with a recovery pose – every time you feel pain, do this simple exercise.
Lie flat on your stomach with a pillow. This can be done on your bed. The pillow should lie just below the top of your hip bones to your thighs. This stretches out your back muscles so that you will eventually be able to do the push up. As you improve – you can use a bigger cushion, working your back out until you can do the exercise below.

If you are able, to the exercise below – has to be done twice a day. Even if only for a few minutes.

Here is another very helpful Pain site: