Left arm pain in 22 year old female. heart related or pinched nerve?

Depends: Diagnosing l arm pain over the computer is difficult. At age 22, the diagnosis would lean more against a heart condition. However, weight, associated symptoms (jaw pain, sob, doe, cp, burning, etc), co-existing conditions (diabetes, high bp, high chol), family history, etc. Can all play a role in proper diagnosis. See a dr. To get the definative answer, good luck.