Poop stuck & stringy poo?

You could have swallowed hair, string, or something along those lines. Never try to pull something out if it is really uncomfortable. Did you look at whatever it was? Could it have been a worm? If you saved the string you should take it so he can make sure it is not a parasite of some type. If your bleeding or anything that is something you must be seen for. As for the pebble poop, eat more fiber and drink more water. I think if you feel ok, there is no bleeding or sign of anything else going on just eat more fiber and drink more water. If something comes out like that again see you Dr.