Is shoulder filler anesthesia very painful...?

I've been stressed about my shoulder line lately, so I'm even looking into shoulder fillers. However, while researching, I noticed a lot of talk about the anesthesia for shoulder fillers... My biggest concerns are how the anesthesia is administered and how painful it is. Since I'm a very timid person, I feel like the anesthesia process is scarier than the procedure itself... If anyone has had this done, could you tell me what the anesthesia feels like or how much pain it causes?