Back Pain Due to Gas
If you eat only fruit before going to bed, gas will be produced. This gas will get trapped as there is nothing else to push it along. The effects of the gas will affect your body all through the night. In the morning, you will get up with back pain. A swollen belly stretches the abdominal muscles, which would then be unable to stabilize the pelvis. Abdominal strengthening exercises would prove futile, if your stomach is distended due to gas. In such a case, your pelvis would not be able to attain the neutral position required to get relief.

Flat Abdomen Gas Pains
Even if you have flat abs, you still cannot evade back pain due to abdominal gas. This is because, the gas would push your intestines into your spine. Such back pain can only be relieved by removing the gas from the system.

Constipation and Back Pain
Constipation puts excess pressure on the bowels. In constipated individuals, the colon is filled with waste matter, making it rigid and stiff. As the colon is situated close to the spine, there is back pain. A constipated person strains to eliminate body waste. This straining increases the blood pressure, traumatizes the rectum and puts great pressure on the spine.