Why I am getting leg pain while motion?

There are quite a few reasons for the concerns that you describe. As you can imagine, the complete differential diagnosis is large and beyond the scope of this discussion. It is important that you discuss these concerns with your primary care doctor as he or she will best be able to evaluate your presenting symptoms, medical history, and decide upon the appropriate medical work up. He or she may decide that further imaging studies are important, or they may recommend you visit a specialist. In terms of the general complaints, it is very concerning that you describe issues with control of your bowels. This can indicate that there is something going on in the nerves in the lower part of your spine. Sometimes degenerative disc disease can cause these complaints. Other causes can be mass lesions in your pelvic region, or neuromuscular disorders. The pain that you describe that radiates down your leg may indicate nerve irritation, and again the best person to evaluate this would be your primary care specialist. Depending on what they find, epidural steroid injections, NSAIDs, muscle relaxants or perhaps even surgery may be recommended depending on what the final diagnosis is.