I have fatigue, pain in left shoulder blade and throbbing on left side of neck off and on for about a week. ?

Muscle pain: The pain sound most likely musculoskeletal. That is the most common reason for pain like this. You can try proper stretching and anti inflammatory medicine of your choice and warm compress. If pain pain persist have it examined by your physician.

Nerve pain: This sounds like pain caused by pressure on a nerve or nerve root by a disc or spur in your spine in the neck. The pain radiates toward the scapula(shoulder blade). If a rash appears,shingles would be suspected. Consult your Physician if symptoms persist or worsen or if a rash appears.

See your doctor: Many things can cause this but could be referred cardiac pain. You need to check with you physician. Many other things cause cause these symptoms including a lot of musculoskeletal issues related to your shoulder and neck such as bursitis, tendinitis and arthritis This need s to be clarified.