16 y/o male, feeling pulsing on random parts of the body at random times for the past few months. active & healthy; well-balanced diet. what's this?

See below: Filling a pulse at different parts of your body is common.

Its normal: What you are experiencing is muscle fasciculations or involuntary muscle contractions. Everyone experiences them and most are harmless. They can also occur as a result of some abnormal conditions such as polio, spinal muscular atrophy, and more commonly magnesium deficiency. Up to 70% of adults do not consume the daily recommended amount of magnesium. You can get it from nuts, bananas, and spinach.