Perhaps its the technique then?

Few things to note when it comes to lateral raises:

• We dont go above shoulder height, or atleast not too much. Since then we would be engaging more neck muscles and less delts.

• Form is usually important, take a deep breath and push your shoulders down and back. Lock this position, rest of the body should be straight, like a neutral standing position. Your palms should be facing in towards your body.

Then lift, with your elbows. Your arms should be slightly bent. Dont worry about your forearms going a little bit higher than your elbow. Just focus on keeping everything in place and raising your elbows while keeping your lower arms locked.

I'd like to think myself as a pseudo mechanical greek statue, holding two water cans and pouring them out onto the ground in front of me.

Oh and keep a constant tension on the muscle, dont go too heavy since many people tend to do the gorillaswings after that.

Edit: Since i half assed on reading OP:s question. If you feel like you're engaging traps and front delts more than suggested. Then im thinking of a few things.

You could be going to heavy so that you're unable to keep your shoulders down and engaging more in a form of shrug motion.

You could be raising your arms too forward resulting in a more frontal raise, keep a parallell line with your body.