Occasionally (like right now), I get a sudden sharp pain that makes me stop breathing for a second, then the pain goes away. It doesn't seem to be serious, as the pain isn't really spreading anywhere and I'm doing anything like sweating, breathing heavily, or anything. However, unlike usual, right now when I inhale too deeply or anything like that, my chest suddenly hurts slightly. What could be the reason for this, and is this a sign of anything serious?