There can be several reasons for this pain and it will be very hard to pinpoint the cause without the benefit
of an actual physical examination and neurologic examination. Here are some causes.
Nerve root compression due to spinal cord problems can cause pain with a certain area of distribution which
are known as "dermatomal levels". Your back pain and stomack pain that spreads to some part of your
legs can be caused by a single dermatomal nerve root compression. The compression can come from a slipped
disc or any thing that can impinge the nerve in this area.
Degenerative changes to the spine can also cause pain in this distribution and some of that pain can be
referred to the stomach and to the legs.
Problems with the gastrointestinal, urinary (kidneys and bladder), and the female reproductive tract can
result to pain in these areas with the pain being referred or transmitted to the back and legs.
I suggest to have this formally evaluated by a doctor to have the benefit of a physical examination. This
should probably pinpoint the cause.