I Started Taking Amphetamine Salts 3 Months Ago, Started 10mg,

I started taking amphetamine salts 3 months ago, started 10mg, then 15mg and now 20mg once daily seems to be quite effective for me. I caught a cold at the very beginning of January, which also coincided with the upped dosage to 20mg. The cold is gone, however I still have a nagging dry cough. It feels like an irritation in my chest causing me to cough. Is there any chance this could be medication related as opposed to the dragging on of this virus?