I have numbness and tingling in my upper left arm what could it be?

Hello. Thank you for posting.

Injuring a nerve in your neck may cause you to feel numbness anywhere along your arm or hand. A severe strain or sprain is also possible. However, sometimes numbness, tingling, and pain in your left arm could be an indicator of a more serious condition like a heart attack, stroke, or a side effect of diabetes. A doctor's evaluation is needed.

Helena