GREAT question brother. Here I am, trying to get through a match of questions this evening and you hit me up with this one, which is just too damn good to gloss over. So let me get comfortable cuz this is going to take a minute.
Ok, so on or off gear, something has to change in order to get your side delts to pop. Wish I had some pics to look at, as this would help me with a theory. If you want to send one over, drop me an email over at the Next Level Nutrition page, here at Naps. Just remind me about our conversation. I'll reply to you and then you can send a pic. But without seeing you, I can give you a couple theories.
First, you have strong traps. Your traps can easily take over when you are doing lateral raises and they can do some of the work in your over head presses. Adding more sets is going to do little to nothing if your traps are doing all the work. So make sure that when you are doing this movement, stand tall, chest out and focus on using the intended muscle. Do NOT pinch your traps together. Often times, I see skinny little guys whipping around heavy DB's on this movement, and using all momentum and traps. I'm standing there next to them, often using 1/2 the weight they do, but my delts are big, round, and always been a stand out body part for me, once I learned to contract them. So use a weight you can control and focus on getting a squeeze at the top.
Second, maybe you are using the wrong rep range. Everyone is different and each muscle group requires a different rep range. If you have been using an 8-10 rep range, go higher. Maybe you still want to do some heavy work, but also include some higher rep sets.
The good news is, delts are a small muscle group and much easier to bring up than something like legs or back. I'm confident that with the right plan for you, you can improve those shoulders. I do work with clients that specifically have goals of bringing up a specific body part. If you want to hire me, along with your diet, at no extra cost, I can develop a training plan that will optimize your delt training and through week by week progress pics as well as video clips that I can use to help you adjust form, I'm confident that we can get you on the fast track to cannonball delts. Once again, hit me up at Next Level Nutrition for that. And either way, I'd be happy to give you feedback like I mentioned earlier.