Hi, Last Week I Woke Up In Pain In My

Hi,
Last week I woke up in pain in my back at my right shoulder blade, up neck and down my arm to my elbow. I go the gym regularly so I'm thinking it's from this. I rested for two days but it's still not great the pain has gone down a little but it's still sore. I want to go the gym but I'm afraid I'll do more damage. I haven't gone to a doctor. I've never had anything like this before.