I am having a very severe relapse of my post-concussion symptoms after what strikes me as a completely innocuous event: three days ago I accidentally hit my sternum on the corner of a dresser - I did not hit my head, neither did my head/neck move quickly as a reaction to the hit. I started feeling awful immediately afterwards, including symptoms that I had not been experiencing for months (nausea, intense headache, intolerance to screens...).

I am 13 months into PCs and I am used to the regular setbacks that follow minor events. But usually headaches are the only symptoms, and they only last a few hours; also, these setbacks had become less frequent and less severe as I learned to control the reaction of anxiety. This time I am feeling as if a new concussion had happened, and I can't understand why (I was not anxious at all after the hit since my head was not involved). Any idea/advice?

Any painful event can start a cascade of response chemicals. It can also create a startle response or an anger like response that will cause this cascade of chemicals. Although you were not anxious about the event, your body has responded in a way that is similar to bumping your head.

The sternum can a very sensitive spot, even if just for a short period.

I know that I can experience a painful event that triggers me for at least a day. I might end up shaky and nauseous with what I call a mud headache.

Try to relax and treat your headache and you will get through this.

My best to you.

Thank you very much, Mark - words of wisdom, as always. I cannot say how grateful I am that you (and others) generously share their time and knowledge. PCS is a lonely path and this forum is a blessing.