I'm really concerned about this persistent neck pain I've had for the past three days. It's spread to my shoulders and sometimes even to my head, which really bothers me. I saw my primary physician, and I'm on some medication now. But this morning, I noticed my shoulders seemed a bit swollen, and there's this strange, hard muscle on the left side of my neck, right below my ear. It's not a visible lump, doesn't move, and isn't painful, but it's strange. Could it be a muscle issue? Oh, and I've had a common cold and a bit of cough at night, but no vomiting or fever. What do you think is going on?