Healthy people can have symptoms, and unhealthy people can have no symptoms.
If you have to choose between having a body that “feels 100% perfect” or “works 100% perfect,” what would you choose? I would choose for my own body to work 100% perfect. To illustrate, you can take enough drugs and alcohol to feel invincible for one night! But when that high crashes down, the next morning, you’re in a worse place than you started!
If your nervous system is not working properly, your health is spiralling downward, called Accumulative Destructive Survival Value. You may “feel fine” now, but only because your health hasn’t deteriorated so far that you feel it yet.
On the other hand, if your nervous system is working properly, your health is spiralling upward, called Accumulative Constructive Survival Value. You may still have symptoms, but only because your heath hasn’t retraced upwards enough that you feel better yet. What you need here is simply the necessary time for your body to heal.
I can’t emphasise it enough: “feeling fine" does not mean that you are healthy. If I could wave a magic wand so that you could feel instantly better after an adjustment, I would do so in a heartbeat. The reality is that is not how the human body heals.
Similarly, the purpose of the upper cervical correction is not to make you feel instantly better: it is to allow your central nervous system to work instantly better with the ultimate end product of feeling better.