My son is like this too. His anxiety is so bad some days that a task may make him vomit. OT has been helping us with this. My son has selective mutism, he uses a communication device when his anxiety flares up. He is having a lot of trouble sleeping too. He is scared that spiders are going to come and get him. I have no idea where this came from, but he has been saying it since he was very little and he is 10 now. At least he is able to express that he is scared. My son doesn't tell us, he just stops talking and literally freezes up. Maybe try doing the task yourself first and show him that it is okay. We have a teddy bear that we used when he was younger that went to doctors appointments. His pediatrician was amazing and would do everything to the bear that she was going to do to him and he was more comfortable that way.

My son has intense fears of certain things too, i.e. The beach, but it's gotten a lot better. We are sometimes now able to go to the beach again, for example, because we remind him he can collect rocks for his rock line collection and he'll get closer to whatever number he is aiming for. That's his motivation now. However, before 2, he absolutely loves the beach and I couldn't keep him out of the water. I miss those days of no fear of the beach but at least I can on occasion convince him to get in the car and head to the beach and get out of the car and step foot ( almost always A shoes foot) on sand somewhat near the water, and potentially a foot in the water. Much better than him getting aggressive/running away/or completely shutting down when the word beach is mentioned. He also went through a phase of wanting noise cancelling headphones or for me to not make any sounds (i.e. when cleaning), no playing music...And got stuck in repitive speech telling me over and over to stop making noise/not talk long after I had stopped...i had to get him used to the sounds again (he had been with his dad out of state who let him have the headphones). I compromised and then gradually increased the sounds and he seems just fine with sounds now. Gradual desensitizing him from his fears is working especially when I pare it with a reward to motivate him.

He does fine with loud, mechanical noises like air hand dryers and such, but if a person is loud he will either run away crying, or curl up and rock. He once got stuck in a play place at a McDonalds because someone was loud.