I don't know why I have so much anxiety. It's like PTSD. I imagine it has something to do with brain functioning. People are born with different levels of sensitivity to different things. Neurons fire faster and harder in one area than another. Reflexes are set off more easily. Some such people become great artists and athletes. Some get so overloaded they lose the ability to function at a normal level. When every other thought is, "I'm about to die," you don't have time to think about how to make the color on your palette more beautiful.
Unless, that is, you work through the anxiety. That is why I am so attracted to meditation. By making an effort to empty your mind, you discover the thoughts that don't usually come to the surface, but which often control behavior from the unconscious. If you find yourself frequently anxious in certain situations, for no clear reason, you might discover the reason by meditating. As the meditation unfolds, you may remember a situation in which you got anxious. You don't try to think about the situation, because the point of meditation is to let go of striving, let go of attempts to channel thought in specific directions.
As you sit with the situation, you get the holistic sense of all the feelings associated with it, and all the times you have felt those feelings. And sometimes, you can reach back into one or more of those times, and remember the original traumatic experience that keeps getting triggered. In my case, there is a memory of some harsh treatment of a very small child. Too harsh. It set up an experience of "hell" - that which cannot be endured. It taught the child that hell could happen because of something you did. But you might not know in advance that what you did was worthy of hell. So, when you are thinking of doing something that you haven't done before, and don't know what the consequences will be, you will be very conflicted.
You will have anxiety around people you perceive to have power. You will have anxiety in social settings, and sometimes you won't know why. It feels like your brain seizes up, and can only think about what to do, how to remedy the situation, or how to escape the situation. Until you calm yourself down enough to really look at every thought and feeling, you won't know why your body and mind go into a lesser or greater panic, and whether that is justified or not. Hopefully, you begin to suspect that panic is not justified, long before you have any idea of why you panic.
My whole lifetime has been dedicated (on some level) to walking back my anxiety. Through my long-term meditation practice, with help from loving friends and teachers of co-counseling, I have gained enough serenity to notice - in the moment - when I go into some level of panic (sometimes, not every time). In the midst of those experiences, then, I have some chance of walking back the anxiety of the moment, and dealing with reality from a place of calm.