Answer:
Yeah, try lifting something extremely heavy and tear it out of it's insertion. My buddy did this to his chest and his chest muscle detached from the should tie-in and curled up in his chest like a snake.
yup. you can outstretch them and actually tear them. also you can get and fluid build up in them if you don't stretch before exercising (doesn't have serious damage, just sore muscles)
--ducktape757
YES!! You can "hurt them" very easily. If you dont rest enough inbetween workouts, or over work your muscles. Stretching is also very important. You need to learn how to exercise. Most people fail with their weight goals because they get too sore. Learn and you will be fine!