Why do I have missed beats?

As long as your heart rate is between 60 to 100 beats a minute, (healthy, normal heart rate), I wouldn't worry too much. Heart arrhythmias are when the heart beats faster than 100 beats a minute or slower than 60 beats per minute.

There is one condition, called a Premature Heartbeat, which might apply.

"Although it often feels like a skipped heartbeat, a premature heartbeat is actually an extra beat. Even though you may feel an occasional premature beat, it seldom means you have a more serious problem. Still, a premature beat can trigger a longer lasting arrhythmia — especially in people with heart disease. Frequent premature beats that last for several years may lead to a weak heart.

Premature heartbeats may occur when you're resting or may sometimes be caused by stress, strenuous exercise or stimulants, such as caffeine or nicotine."

If you think what you perceive as a "skipped beat" is the above, then you might want to lay off so much caffeine, and/or cigarettes.

I don’t know about you but monosodium glutamate messes with my heart so I try to avoid it as much as possible. But if it’s too late to avoid I take magnesium and that settles it right down. But you might wanna get your heart checked out, you are young.

I get that a lot, races. It's odd. Apparently normal in most people, according to the doc.

Same issue for me, comes and goes.

please drink mineral water and add drops of lemon juice as well as salt....
hopefully they are not ectopic beats ....Kindly visit an ECG lab and get the heart beat checked up

You could be standing next to someone really attractive

Beats?

You might be dehydrated.