Bathroom trouble. If its just a pebble, how do you get it out ?

I know there's something there. I can feel it , but I dont have enough in there to have a regular BM. Do I wait for the next shipment or what? I was trying to relax and wait , and nothing happened. So I started rocking back and forth and side to side and nothing happened. Its very annoying because I feel something and I dont like that. I've had this problem before and never knew what to do or who to ask , but I really would like to know. Is there a trick or something?