Are the cramps linked to the asthma?

Hi, l have an interesting situation. Here's my story: my dad has had asthma since he was a child and i was born with it as well. when i was an infant, i suffered from sever bronchitis. right now i am sixteen, and all my life i have battled asthma which has prevented me from doing anything physically strenuous, like sports, etc. i have been taking prescription inhalers to fight the asthma side effects and they have worked amazingly well. the thing is, however, whenever i try to do anything that requires a lot of running, like cross-country, basketball, soccer, etc, i start to get these cramps in my chest and lower sides. my question is this: are the cramps a result of my asthma kicking in, a diet problem, or are they simply something i am going to have to work out of my system gradually over time? i have told people about this, one person said it could be a diet problem, but i am convinced that it has something to do with my asthma. can you please give me some/any info on this? where are the cramps coming from? thanks so much in advance, and please answer seriously, this is very important to me.