Some time at midnight i feel severe pain in my back and upper area but when i go to bathroom have a stool then things becomes normal whats that? &why

Nightime pain: Your clinical symptoms are likely due to gas pain. At night gas from the large intestine will rise to the level of the transverse colon resulting in abdominal cramping and pain. By having a bowel movement you are decompressing your colon of stool and gas and this is what results in the relief of pressure. Closely monitor what you eat during the day esp. lactose and legumes.