Trying to train to Run; need help!

Zanymom

I have been working out at Curves for a few months now but keep getting bad lower back pain so thinking it is one of the machines
causing this. I took a break for a bit and the pain stopped but still worked out on the elliptical and no back pain. Decided I wanted
to train myself to be able to run. Started yesterday and did a jog/walk for just over a mile in 23 minutes. Today I did the same but
had to go at a little slower pace because my calves were tightening up and in pain. Is this normal? What is a good routine for me to start to train to be a runner? Also I need to lose about 20lbs of belly fat I do not gain anywhere else just on my stomach and i'm only 5'2" so it looks like i'm 4 months pregnant and I HATE it. I really want to lose weight. So any pointers would be appreciated. I am in Massachusetts!