Hello Sue and welcome to alt.support.cancer
I peeked in the Google archives and apparently you're "adjusting" to a CPAP.
That took my brother almost a year to get everything just right. (so fatigue can
be a problem for a while). Cancer can cause fatigue, so too radiation, but from
what I've heard it does "kick in" about two weeks after the first treatment.

Are you sleeping on your back with the CPAP? I can't sleep on my back, because
I've got chronic sciatica, which can cause shooting pains down the butt into the
legs. Two things to try are: an appropriately shaped pillow or rolled up towel,
in the small of your back or sleeping on your side. I don't know if radiation to
the abdomen can affect the lower spine. Perhaps there's a scan (CT?) that could
look for trouble in that area? I don't know your age, some of us have
osteopenia, and/ior slight disc problems which too can cause "sciatica"
depending on how we sleep or bend.

It's strange to me that they told you radiation can't cause diarrhea because
this website says "The most common side effect of pelvic irradiation is diarrhea
(easily controlled with antidiarrheals), dysuria, rectal irritation, fatigue and
mild skin irritation. " Dysuria means painful urination.
http://www.radiology.uiowa.edu/Radshortclerkship/RadShortClkship/LectureNotes/Ma
yr.htm

So I'm wondering if you're getting dehydrated from the diarrhea, which in turn
is lowering your blood pressure ? If I'm right about dehydration, perhaps that
can cause potassium and magnesium imbalances which could cause leg pains?  More
likely, I think, cramps than sharp shooting pains though.

Can you ask the doctor(s) about an antidiarrheal ?

They sell "nutritionally balanced" meals in a can, also there's "sports" drinks
that claim to help to balance one's potassium and magnesium (electrolytes). I
forget their names but I would feel more comfortable if you asked your doctor or
someone else here recognized your leg pains as being caused by that. (before you
started any of those drinks). Perhaps Mike will be around later and have an
opinion.

There's tips here from a post I made earlier, from the FAQ
http://tinyurl.com/35z7g

Hopefully Steph will be around soon, perhaps he'll recognize the reason for the
leg pains.

So hang in there for more opinions, because I'm not a doctor.
J

Sue,
Afterthoughts, Gatorade ?
And I wonder if you've got a touch of gastro flu?
I got hit yesterday but it's gone now, but I did not have leg pains.
J

Pelvic radiation often causes diarrhoea - it lasts a few weeks.
Many patients feel tired.
It doesn't have any effects on BP, and doesn't cause pain in the legs