Imagine you’ve just completed a tough upper-body workout. Your muscles feel a bit tired, but all in all you’re able to go about the rest of your day just fine.
The next morning, you wake up and realize the back of your shoulder blade feels stiff. When you rub your shoulder muscles, it feels like you’re prodding a little gumball under your skin. Every time you try to move it around, the area feels tight, with slight pangs of pain.
Over the course of the next few days, your back slowly loosens up and eventually your shoulder returns to feeling normal. It’s probably something you’d like to avoid or minimize in the future if possible, though. So what was going on with that muscle knot?