Chest Tightness

I am on my second month with Accutane at 40mg. I am very paranoid since I suddenly felt tightness of my chest. I was touring my friends around here in Melbourne for two days. On the second day, I felt like it's hard for me to breathe in air effectively. I did have a good night sleep last night though. I rang my derm and said chest tightness isnt related to accutane and Ive seen a GP today who said the same thing. My GP said maybe it's because I have been out and it is starting to get really cold here in Melbourne. He prescribed me with 50mg prednisolone for three days. I asked him if Id still be able to take my accutane and he said yes. He said I need to come back to the clinic if I don't get any better after 3 days. Anyone who had similar experience?? Please tell me. I am too scared I wont be able to finish my whole course especially now that I am slowly gaining back my confidence