In my experience, the best cure for this is exercise especially running or weight lifting. It trains your brain to endure difficult and strenuous tasks. Furthermore, the endorphins that are released subconsciously start to build the association between feeling good after facing a stressful situation. You begin to look at stressful situations, not as something to be feared but something to be conquered. I used to be the biggest introvert because social interactions stressed me out. Now I thrive for that feeling of, "Man this isn't as hard as I thought it would be"