There are differences in symptoms between spinal stenosis pain and herniated or ruptured disc pain. A herniated disc often is more painful when sitting and relieved by standing or walking (opposite of stenosis). A herniated disc can cause sciatica (so can stenosis) and can be a result of degenerative changes in the disc. Sciatica will commonly radiate or travel down the backside of the thigh, into the calf and sometimes the foot itself.>
How to: Get in a standing position, with one foot about a foot's distance behind the other, hips in line. Your feet should be flat, and your legs should be straight. Cross the back foot behind the front one as you reach your arm on the same side overhead. Return to starting position. That's one rep. Do eight reps on each side. Do three to four sets before moving on to the next move, resting for 30 seconds in between each set.
During pregnancy a woman’s abdominals get stretched out. There is no way to avoid this with a growing baby. Muscles work most effectively when they are at an optimal length. Not too short and not too long. The lengthening that happens during pregnancy puts the abdominal muscles at a decreased advantage for working. This decreases the amount of support they provide for spinal stability.  
You’d think so. But consider this story of a motorcycle accident: many years ago, a friend hit a car that had pulled out from a side street. He flew over the car & landed on his head. Bystanders showed their ignorance of spinal fracture by, yikes, carelessly moving him. In fact, his thoracic spine was significantly fractured … yet the hospital actually refused to do an X-ray because he had no obvious symptoms of a spinal fracture. Incredible! The next day, a horrified orthopedic surgeon ordered an X-ray immediately, confirming the fracture & quite possibly saved him from paralysis.
You're more likely to get a hip flexor injury if you've had one in the past, you don't warm up properly before engaging in athletic activity, your muscles are already tight or stiff, or your muscles are weak from being overused. If, while exercising, you try to do too much at once in too short an amount of time, you can also put yourself at risk for a hip flexor injury.