Asthma can start in adulthood even though it more commonly begins in childhood . It is a condition increasing in its prevalence. Many people suffer from it so if you have it you are not alone . Asthma symtoms are often like the ones you describe . A nighttime cough is also a symptom along with wheezing when you breath . Attacks can be triggered by many things . You should check it out specially as it gives you trouble breathing and this can be scary. You need to breathe to live . It could possibly be another condition . If you had a bad flu in childhood sometimes this can lead to another condition which is also common . If it is asthma dont worry too much because there are good treatments for it and it need not be something that necessarily causes interference with you life . But you SHOULD get yourself checked by a doctor .

Hi,

Asthma is a lung condition that causes wheezing, coughing, and shortness of breath. It is triggered by irritants or some allergen, like – cold air, viruses, tobacco smoke, dust, pollen, moulds, and animal dander. Some people have coughing or wheezing only during exercise (called exercise-induced asthma).

An asthma attack may last a few minutes or for days. Attacks can happen anywhere and at any time. It is very important to get treatment for asthma to live a healthy, active life.

In asthma, the lining of the airways in the lungs is swollen, even when there are no symptoms. When exposed to irritants or allergens, the airways become more swollen and begin to make excess mucus. The tiny muscles in the walls of the airways begin to contract. These reactions decrease the airway openings, making it harder for air to move in and out. The whistling sound of air moving through the narrowed air passages is called wheezing. The extra mucus in the airways causes coughing.

The symptoms of Asthma are

The patient has difficulty in breathing, wheezing, coughing, shortness of breath and tightness in the chest.

Asthma is a lower airways disease and is caused by constriction in the tinier generations of airways deep within your lungs. Attacks cause a tightening in the chest, breathlessness and dry cough and can be triggered by smoke, exercise and heat/cold.
I strongly doubt that several isolated incidences caused your asthma, they could’ve maybe caused an attack. It’s normal to have some minor irritation after breathing in strong chemicals, but the degree of that irritation is where the key to whether or not you’re asthmatic lies.
Some people “cross over” into adult asthma after having it their entire lives (like I did), some have it as children and never have another attack after puberty, some start having attacks after puberty.
The only person who can effectively diagnose and treat asthma is your doctor. He/She should do pre and post bronchodilator pulmonary function testing (PFT) and may even refer you to a pulmonologist, a doctor who specializes in pulmonary diseases.