I assume that muscles have pain receptors ("nociceptors"?) that fire when the muscle is under excessive strain or even tears or becomes injured.
I also assume that similar pain receptors exist for your tendons and ligaments.
I'm wondering if there is any difference in the types of receptors that exist for muscles vs connective tissue. I ask because I compete in sports where I definitely strain/injure muscle, and I also occasionally strain/injure tendons, and the pain feels completely different.
Muscle pain is sharp, immediate and activates when I move the injured muscle, and makes the area sore to the touch (e.g. I try to massage it). As soon as I stop moving or touching the muscle the pain is gone.
Tendon pain is radiating, burning "toothache-like" throbbing pain that sets in and becomes inflammed about 2 or 3 minutes after I move the area that is injured and sustains for several minutes thereafter.