Ouch, that sounds rough! It's smart that you're thinking about checking your form—that can make a huge difference. For alternatives, you might want to try the landmine press or lateral raises, as they’re usually easier on the shoulders. Dumbbell presses with a neutral grip or even lighter...
I agree with you creatine do help a lot at first but then the process get's slower because our bodies also produce creatine. It maybe possible that your body does not need creatine anymore.