Dzgochenkiid

Ok thanks

Im new to the game and just joined about 20ish hours ago. I made it to fuchsia city where i saw in the trade chat that someone (there name was Krikke) was selling a riolu for 20k. I had messaged him and said i had 21k and wanted to trade. He agreeded and we had traded in the fuchsia city pokemon center. After finishing the i went to add riolu to my team but i couldnt get it out the box. There was a lock on its slot thing. Has his happened to anyone else? Edit: i tried to add a picture but its not goning through