The left side is best because you get the best blood flow, and it keeps your uterus off of your liver. That's why so many are told it's the best to sleep on :) it's not just a labor thing
It's bad to lay on your back, your uterus presses on an artery and reduces blood and oxygen flow to the placenta and can cause other issues for you. according to my ob
the left side (as many are told is best) is mostly just for when in labor. I and many other have found it more comfortable on the right, if you were a belly sleeper like me try laying on your side almost on your belly with a knee bent up and possibly proped up on a pillow it helps.
Left is the best to lay on because of blood flow. But I'm pretty much always on my right. My daughter is always on my right side so laying on my left hurts haha. But it's not bad to lay on your right side, so whatever. As long as it's not the back
they say it's best to lay on your left side. but I'm going through the same thing. I can't get comfortable in always changing positions every couple of mins.