Symptoms: shortness of breath, muscle twitching everywhere, chest pressure, upper abdomen pulses. my cardiologist thinks its nothing. what should i do?

Correct?: Your cardiologist is hopefully correct, but i would do a couple of things to be certain: first, i would check and make sure the BP in the arms and the legs are close to each other, second i would have an echocardiogram.

Chest pain: Get a second opinion. This could be nothing but yuou should talk with someone who does an exam and explains things to you.

Trust him: Your cardiologist spent 9-10 years training to know when things were important and when they were not. And in general, physicians tend to practice conservatively so as not to miss anything. For these reasons, the fact that you are a young male, and the nature of your symptoms (which sound like anxiety). I suspect they are right. If you don't trust them get another opinion.