I have had a pain in my left shoulder & neck for about 14 hrs. It is dull & hurts more if in certain positions. Could be heart related or sleep wrong?

Shoulder & neck pain. Your left shoulder and neck pain lasting 14 hours, dull and positional are unlikely to be cardiac, and more likely due to musculoskeletal as in sleeping wrong. But it would be virtually impossible to determine the cause based on your descriptions alone. If seriously concerned, please see a physician for evaluation and treatment.
Prob not heart but.. If you have any associated shortness of breath, chest pain, dizziness, seek medical attention asap. If only involving neck and shoulder, conservative management should work. Ice, heat, stetching should help. If it doesn't clear in 7 days, see doc.