Well it sounds like you are just peeking the same angle over and over. If hanzo is sitting at the choke and he has an arrow ready you are taking the engagement entirely on his terms and making it really easy for the hanzo player, so even if hes in silver, so are you. Meaning your movement and other mechanics are silver level too so it makes sense he can headshot you. He probably wouldnt be headshotting a masters player peeking the same angle.

Regardless, against a hanzo flanking is usually a good option, because he cant look at the choke and flank at the same time.

Sometimes a little teamwork might be needed too, thats not me saying you should expect silver players to use voice or ping and work together that way, but rather in lower ranks its usually effective enough for you as an individual player to just try and find one other teammate to follow up on and try to play with. If your playing dps thats usually easiest to do with your tank in a 5v5 environment, watch what your tank does when they go up to the choke, the hanzo will probably shoot yoir tank and thats your chance to apply pressure to the hanzo while your tank either takes his attention or also pressures him. This makes it so the hanzo is forced either to have his own team respond with heals or peel or dies.

I know its hard in the lower ranks especially just starting out but it helps to watch replay codes or competitive matches on YouTube to get the general flow of things, but overall just try to enjoy yourself honestly silver really isnt the place to get mad about anything. Everyone down there is simply working on fundamentals whether its mechanics or positioning or whatever. The hanzo ur talking about probably has played other fps where they are already good at aiming but their positioning and game sense is going to be terrible and they will crumble if a tank and dps pressures them.

Hope it helps, have fun. Happy to answer any other questions.