I'm a 17 year old girl I weigh 107lbs and I'm 5'4. I'm a skinny person basically. I had flag football tournament and during one of the games a girl on the other team was running my direction and I got in front of her to pull her flag. This girl then lean forward putting her shoulder out first and hit me right in the middle of my chest. I'm a skinny girl I don't have big breasts my rib cage is visible all around. I fell to the ground and gasp real hard for air and starting coughing really badly. I had to stay on the ground for a few minutes then I got back up and into the game. I didn't get the wind knock out of me but now I am on day four and I still have sharp pains in my chest whenever I breath hard, laugh, cough, push or pick up things. And when I put my arms in front of me I still have sharp pains in my chest. What should I do???? ER, doctor, or nothing??