I know a doctor is the only way to know anything for sure, but I'm still very interested in hearing what everyone thinks...

So my left shoulder started feeling a little weird two days ago. I had a shoulder thing once before, but it was my right side. The left has always been fine.

The pain is not constant. It's also probably more of an ache than a pain. Although, I'm not entirely sure what the differences are between the two.

As I was saying, the pain is not constant. Sitting here typing I feel normal. It's only when my shoulder is put in certain positions that it starts to hurt. It doesn't hurt a lot, but I definitely feel something that doesn't feel good.

If I do the motion of a lateral raise, it doesn't hurt. If I do a front raise, it doesn't hurt. If I do a bent over barbell row (or any row), it doesn't hurt. If I lay down and bench press an invisible bar, it doesn't hurt. If I do the motion of a dumbbell fly, it doesn't hurt.

It appears to only hurt when I'm in a double-bi type pose. You know, like if you were doing overhead dumbbell presses. In fact, doing a pretend overhead press hurts. It doesn't hurt when my arms are fully extended or near fully extended in that position. It only starts to hurt when I get near parallel or below it.

I am about 80% sure that the cause of this shoulder pain was sleeping in a strange position. You know sometimes you sleep on your hand or something and you wake up and your hand is asleep? Well, very recently I woke up and my left shoulder was asleep due to the very weird position I must have slept in.

Actually, now that I think about it, in this sleeping position I am on my left side with my left forearm/hand under the pillow and my head on top of the pillow with all of my weight on my left shoulder. If I think about it some more, I realize that this position is VERY close (if not totally identical) to the position my shoulder starts to feel pain in. Change that 80% above to 99%. I am 99% sure my shoulder hurts due to sleeping in this position.

My right shoulder, while not in any real pain like the left, also feels a little strange the last day or two. This would make some sense considering that upon waking up from this bad position on my left side, I roll over on to my right side in a similar way.

So, the cause is most likely the way I slept. What I want to know is what the hell is it? Any guesses? Besides having a doctor check it out, any other opinions or ideas?

Thanks in advance.