Is there a physical reason why my left carotid artery specif...

Is there a physical reason why my left carotid artery specifically would have plaque?

It's not known for sure what triggers the build up of plaques inside arteries other than injury. So why the carotid artery in particular is hard to say.

The only thing you can do is treat what you have and try to prevent further atherosclerotic plaques from building up -

If you're a smoker, stop. It's the biggest favour you'll ever give yourself.

Get your cholesterol monitored ... Make a lifestyle change to lower the fats in your diet. With atherosclerosis, the doctors seem to like you to go below 50gm of fat per day. This will reduce the amount of LDL (the "lousy" cholesterol) your liver produces and ships out around your body, so not so much will deposit in your arteries.

Exercise will help increase the HDL (the good cholesterol). You want that increased because it acts as a scavenger of the bad cholesterol.

Your doctor may prescribe statins (Cholesterol lowering medicines).

Increasing the HDL and lowering the LDL will not only help stop plaque building, it can actually help reduce the existing plaque build up with time.

As you're aware, plaque in the carotid artery will reduce blood flow to the brain, which is not good. If allowed to build up further, the buildup can cause stroke. What is also worrisome is that depending on the structure of the buildup, if it's not diffuse, but clot like, a piece can break off and cause sudden stroke or even death.

So, I would imagine you'll want to do everything you can to stop the progression!

Good luck.