Hi guys

Starting at the base of my skull, the left side of my neck and my left shoulder are extremely tender and swollen and have been very painful for the past few weeks. Recently I've found myself trying to massage the muscles in hopes of releasing some of the tension but to no avail. I've also noticed when I press on a spot in my shoulder that is particularly sore and tight (it's the left shoulder on my back right above the collarbone) I'll feel a pins and needles/tingling sensation, or even a sharp zap, further down my back. Almost like something is living in there and I'm angering it so it moves a bit south. Obviously I know that's not the case but you get the point. Anyone ever had this before or know what it could be?