Chest pain between muscle and skin lasts less than 1min and happens throughout the day all tests normal no family history of heart prob. 20yold. pain sometimes in middle left under or middle of my left chest. pain 3-5/10?

This is probably: from the muscles and bones of your chest. You could try a short course anti-inflamatory over the counter medications and see if it makes a difference.

Chest pain in youth: With your age and gender and with "all tests being normal", the pain is most likely musculoskeletal in origin. try heat pads when pain is severe and if you are doing exercises that stress the muscles in the chest, take a break

Unlikely the heart: Temporary pain like this can be muscle, a chest source or abdomenal source like gas. What will clarify this is what makes it occur and what makes it resolve, are you able to identify any physicial findings at the tiime of the pain - like tenderness on palpation, increase or decrease of the pain with any maneuvers, etc. Discuss some of these aspects with your physician.

Atypical chestpain: The pain most probably from musculoskeletal in origin. One of most common cause is costo chondritis that is inflammation of the cartilage at the end of the ribs, the location and character of the pain sounds like costo chondritis, it is nothing need to worry about, but could be nagging, usually anti inflammatory medicine helps.

Chest pain: Sharp intermittent chest pain with all normal testing at this age is usually costochondritis or chest wall inflammation. Especially if it worsens with movement and deep breathing. You may try to take an anti-inflammatory such as ibuprofen and see if this helps. There is also a condition call pericarditis - inflammation around the sac of the heart but this should have be found by your doctor.