If you work at a desk, you may spend a lot of time with your shoulders hunched without even realizing it. That's been my experience and I recently developed muscle knots in my shoulders.
I thought they might have come from overdoing it at the gym, or straining a muscle while playing tennis, but when I saw a physio, they told me that the knots were most likely caused by my muscles becoming tight from too much time sitting at my laptop.
