I was playing basketball and someone charged directly into the middle of my chest. It kind of winded me and it hurt to breathe for a bit. I couldn't get up from a laying down position either. After some time passed I could get up properly and it seemed to go away. I played basketball again and the same thing happened, i was hit in the chest. I went to see the doctor just in case. I told him that I could hear a cracking sound when I twist my body he said it could be due to cartilage overlap which is nothing serious and ran several tests to see if i had any internal injuries. He didn't however account for the pressure i feel. Its easier for me to feel pressure when i press down on my chest and when i stretch different positions such as twisting. It feels like if i ever get in a fight and get punched my chest will collapse or something. I feel vulnerable, the pressure i feel is easier to feel than before. What should I do? I've already waited 2-3 months since the 2nd injury.