Lateral dumbbell raise alternative using dumbbells

Secret to nice shoulders is rear delts.
Secret to rear delts is the reverse pec deck.

More than likely some impingement going on in there. Make sure you are working your shoulder blade too, as that is a big contributor to shoulder movement. I would give it a little rest maybe do some Y' raises instead of full on lateral

Lighter weights until you build up strength, or grab some resistance bands and do the same motion.

Agree with the comments in this thread RE: impingement and mobilization. That said, I've found cable lateral raises to be effective. I use a form really similar to this.

The standing lateral raise machine looks really cool, but I've yet to workout in a gym that has one.

Shoulder press is by far the best delt exercise. If you can do it, do it.