I wanted to get some cardio in today, and what I do for cardio is basically speed walking alternating with running. And I tryed to push myself to a higher speed, and it was going go for a while then right below my waist on my back right side, I feel pain, alot. It feels like I could have strained something. What could this be or what can I do for it?
Yes, that would be something to do if the pain persists--see your doctor. I would also suggest putting an ice pack on the area and resting. Don't try to run again until it stops hurting.
It's not necessary to push so hard that you risk injury--which can be easy to do if you aren't used to exercise. So... take it easier!