For about a week, I have been experiencing a pain in my back on left side, about midway up. This comes usually when I lie down (I sleep on either side), and by morning, sometimes, I feel pain (like a muscle soreness) around my ribcage on the left side. This is not an excrutiating or sharp pain. It actually feels more like a "soreness" or muscle pain. The pain sometimes goes down a little farther to my lower back, again on the left side.

I am concerned because of the location of the pain and the fact that it seems to dissipate as the day goes on, but comes back in when I lie down again.

I am drinking an average of 100 oz of water a day, my protein intake is an average of 120g a day. I take Atkins Basic #3, Omega Oils, and Calcium. I am urinating regularly (LOTS with all that water!) and there is no discoloration (except from the vitamins).

Has anyone else experienced these symptoms or have any ideas what this could be? I searched the web for ideas, but I found no reference to a condition with my symptoms. I never had any such symptoms prior to beginning Atkins about 6 weeks ago, and am wondering if it is related at all. Naturally, I turn to my knowledgeable friends on this forum for any ideas.

I used to get pains like that - for me it was because I was lying on my side, and my legs were throwing my back out of alignment. I now sleep with a pillow between my knees to keep the leg up and not pulling on my back. Takes a bit of getting used to, but it works wonders!

Any chance that you're constipated? That sometimes produces back discomfort like you're describing in me.

No, not constipated. I haven't really had trouble with that, but if I do, I just eat a few slices of pepperoni or have some spinach and I'm good to go (literally)!