29 year old female. left arm pain for a few weeks now. is this heart related

Possible-not likely.: The vast majority of pains from heart are felt in torso, though sometimes also perceived (radiate), as with other mediastinal sensations, into the shoulders & arms (all innervated by cervical nerves 3, 4 & 5) & brain/mind cannot always correctly identify the origin. While arterial disease typically begins in childhood, arteries enlarge, heart pain quite rare at age & most arm pains come from arm.