Cracking sound in chest after injury?

Beginning of July, I was in a serious car crash which lead to me having emergency operation and I have recovered fully now. It was a head on collision, both going about 50mph so all the injuries were mainly caused by the seatbelt. However, since then I keep getting this weird cracking sound in my chest whenever I stand up, do certain exercises such as running. It sounds strange like a thump inside the body and it's pretty loud and I was wondering if this could cause problems such as joint pains or something similar in the future? I mean I'm only 18 and I do lots of sport which will cause it to crack even more

Thanks