I agree with the last post! You need a thorough exam to determine what is going on. Why do you suspect diabetes? If you think you could be diabteic...don't wait, the sooner you start treatment...the better. If early enough you can turn it around with diet and exercise. If you're just looking for why you have the pain, see you doctor, early intervention is key to everything. Take care!
you said it is undiagnosed diabetes ,you need a thorough medical exam to get to the bottom of this. Do not assume that it cause lower back , stomach and leg pain and threaten your life.
I really don't think so, I've never heard of it. But your back could be causing your leg pain like Sciatica.