Well I'm 17 and have quite bad asthma. Recently I started using a jump rope (skipping rope) in the afternoons after work to try and loose a few pounds and get fit after years of being unfit due to asthma. After about four days of this I suddenly got violent chest pains and now I'm totally unable to use the jump rope because every time I do I get violent stabbing pains in the center of my chest. I also have been coughing a lot with a chesty cough and have been bringing up yellow phlegm in the morning.
Now I've never had chest pains like this before, and I'm wondering what exactly is the cause of them.