Thanks for providing more information.
Firstly as you have wheezing, shortness of breath, cough, sleep apnea so you shouldn't ignore your symptoms and it can increase the risk of lung cancer.
You need to undergo Chest X-ray, spirometry, CBC, ESR, Echocardiography and a clinical examination by your regular doctor.
Now your main question is that you feel such symptoms when you exceed cigarettes more than 4 a day.
So this is because of the fact that high amount of nicotine impair your pulmonary function test.
Everyone has his own capacity to tolerate nicotine however it's effects are same and they 'll also get same symptoms in next few months to years if they continue to consume one pack of cigarette per day.
All cigarettes can cause damage to the human body and even a small amount is dangerous.
You should concern about your current condition which shouldn't be left it untreated.
I hope this helps.
If you have any further query then feel free to ask.
Positive feedback and bonus are highly appreciated.