Is the Feeling of Tightness Just a Sense of Overworked?

Is the sensation of tightness just, or essentially, a brain doing something that's going to make us likely to limit activity at which we're doing? I'd say, in my opinion, it's just the body sensation of letting you know that it's been overworked. But it's kind of good overworked. You don't actually get strong when you're in the gym working out. It's the recovery afterwards that actually has all these magical benefits.