29/f. left arm pain sometimes starting in shoulder down to hand and sometimes vice versa. shooting\achy pain. had ekg last week and came back good.

Nerve compression: Sounds like a compressive neuropathy of the upper extremity. I think an evaluation by an orthopedic surgeon is reasonable. Sounds like you need an EMG to find out where the nerve is compressed. Could be at the neck or a more peripheral site. An EMG would show that.

Pinched nerve?: You might benefit from seeing a neurologist or a physiatrist to see if you have a pinched never from neck to the fingers. Ekg is not enough to see if you had a heart attack. Try getting a multifunction cardiogram to see if you have ischemic heart disease also.