Suggest Treatment For Neck And Shoulder Pain

over the last 5 days I have been experiencing a pain on the left side of my neck which is also affecting the back of my shoulder and random pricks on my left arm. the strain on the left side of my neck restick head movements and causes head aches on the left side. I have been taking solpadine to supress the pain on my neck but the random sharp pains on my left arm is concerning me. under the arm pit too.