Upper respiratory infection or an allergy episode can be followed by an asthma.
Every asthma sufferer has own symptoms, and asthma symptoms can vary from one to another attack.
These symptoms of itchy throat accompanyied with dry cough, could be an allergy symptoms or asthma can be manifested just with a cough as a single present symptom.
Strenuous exercise can trigger asthma episode with chest tightness, coughing, and difficulty breathing within the first five to eight minutes of activity.
These symptoms usually subside in the next 20 to 30 minutes of exercise, but, can reappear six to 10 hours later.
One in three young adults, with history of childhood asthma, that are in remission (without active disease) at age of 18, would experience an asthma relapse between 18 and 21 year or between 21 to 26 years of life.
Relapsed asthma , usually, is in mild form with less severe symptoms.

Personally I think it was just an upper respiratory infection!

asthma , allergies are both a symptom of a weak imune system, or dehydration & mineral inbalance. The extra exercise could actually help improve your lung health as the exercise causes our lungs to pump the fluids via blood circulation & deeper oxygenation. the cough sounds like you need more minerals, this can be easily achieved by using unprocessed natural salt(sea) & better hydration, i have had this & have had asthma for 43 yrs until 12mths ago when i started using the salt & began hydrating correctly. check out watercures on the web also an educational site ithyroid.com .