Things can crop up unexpectedly but try not to put "the cart before the horse" so to speak. I found out I was asthmatic at 46 - had an awful winter with Bronchitis twice which degenerated into pneumonia the second time -then I got 'flu. Since i was diagnosed and put on the right treatment I've been fine -had a 'flu jab for winter and took some vitamins and supplements as advised and have never felt better
Forewarned is forearmed - doctors have to check out every possibility and sometimes the things they have to eliminate in the process are scarey. On my 39th birthday I underwent an electromagnetic scan of my neck and head to exclude MS as the symptoms I had could have meant that (worst scenario) luckily it was just a couple of slipped discs in my neck -but they don't tell you that until they have the certainty...
Hope things go well for you too.