I have suffered with PCS since 15-16 years old.
I have noticed it a lot more now in my later years (now 30 y.o) and taken a little more note of what is happening to me.
It is always very central on my chest, directly under my breast bone, making my left side a little weaker. When an intense PSC has started it can even hurt my lower jaw and teeth. They typically last 3-6 mins.
I have found that they will last longer when I am tired, I find I yawn more while having an episode.
If I find that if I am not sitting in my usual relaxed sitting/slouching position it will kick off. Also irregular breathing will start it off.
I think they have happened more now I have pressure and greater responsibilities at work (stress you might say), also home life is far from easy, 2 kids with another on the way a wife that suffers from OCD and anxiety.
I have found that sitting on my legs curled up like a snail, arms pushed out in front, really concentrating on breathing can help ease the pain.
I very rarely get this during the day. Always seems to be post 8pm.