Creatine is notorious for weight gain. It's supposed to be water weight inside the muscle cell, as opposed to under the skin, which is therefore supposed to make the muscle appear bigger and give it more power to lift, therefore putting on thickness that is non-creatine related, but I don't like it. I gain 4 pounds when I take it and that just makes me mad! LOL! I also have a hard time fitting into my pants, so I don't take it anymore. I actually took a pic of me when I was on it, and I am just a little TOO thickly muscled, IMHO.
So you are right- it is water weight gain.
I have a friend, a big guy, who took creatine once and ran into some health issues with it. His doctor told him to get and stay off of it- he said it is nasty stuff that can cause liver damage. But I googled it and could find nothing on the subject. Having said that, people usually cycle it- I believe 8 weeks on and then I can't remember how long off. That might be because of health-related issues.
I always say before taking a supplement, thoroughly do your research.
As for the shoulder, I also had a shoulder injury. One thing my physical therapist told me to do that has helped me tremendously to keep it from flaring up again is never let my elbows dip below the level of my body, or come back behind it, in chest moves (presses and flyes). I don't know if that information will help you, but I thought it was worth mentioning. If I start to feel it tweaking, I'll back off of that exercise.
I hope this helps!
| current weight: 158.6