Rotator cuff injury?

How can i tell if I have a rotator cuff injury, short of seeing a doctor? My left shoulder really hurts if i lift my arm above a certain point and move the arm around. It feels fine when the arm is still or lowered at my side moving around. I have a feeling i did it bench pressing, but I never felt any pain during the lifts or after, until about a day later. I didnt go too heavy either, my last set was about 30lbs less than my max. It started out as little nagging thing then progressivly got worse, and now im starting to get the same kind of feeling in my right shoulder. Some one said something to me about growing pains, which i disregarded/half listened to, because it sounded stupid, but I dont really know. (Ive made some great progress in the past 2 months, gained about 20 lbs, so this is pissing me off because things were going well) Another person suggested it may be a pinched nerve, that sounded a bit off too, but I dont know. Ive decided to take the rest of the week off and next week too. This has happened before, about a year ago, and I just laid off for a while and it went away. But i dont want this to happen again, im planning on seeing a doctor when i get a chance. Just wondering if any of you can give me an idea of what i may have done thanks

I am nursing my left cuff right now.
You can find a lot of good information on that injury from the web.
Some symptoms I recall offhand:
Weakness when lifting arm
Shoulder popping when moving arm
Soreness when the arm is stretched toward the back or across your body.
From what you described, regardless of wether it’s rotator cuff or not, do not lift weights at all or you will make it worse. I did this to mine and it wasted a LOT more of my time.
Weakness when you lift your arm can be a good indication of a tear which is more severe than a strain. You should go to a doctor and get this diagnosed properly.

Three basic injuries: Strain - Simple strained muscle. Even still it's an injury you can't train through. Tear - the muscle has a tear in it. Sometimes surgery is required. Impingement - bone spur grown towards the muscle is irritating it.

If you do have this injury dont fear that you wont be back in the gym. It may be a while is all. People have had surgery and recovered to lift again.

I don’t mean to sound like this is a horrible injury, but I have found that the best reaction to an injury in the gym is to “overreact”. Assume the worst so you won’t hurt it more.
Go to your doctor!

oh yea, the only “growing pain” is either a crappy old sitcom or an emotional issue.