Google has not helped me with this, other than to confirm that others experience a similar problem (though not necessarily the scalp; it seems to be skin in general for some people.)
Usually it’s when I have the flu, but last night I had a very severe but thankfully short-lived bout of food poisoning. Today I’m pretty much fine, other than a bit headachy from lack of sleep since I had to run to the bathroom every 15 minutes or so for a large part of the night.
Today my scalp, specifically along the part, is quite tender to the touch, just like it is when I have a bad case of the flu.
Could it be the aftermath of a fever, somehow? I didn’t take my temperature last night, but I did have bad chills/flush, and would not be surprised if a thermometer registered an above-normal temperature. I don’t think it is dehydration related, as I drank quite a few glasses of water to compensate for the, er, outflow.
(MODS - move to IMHO if you like; this seems right on the border of a factual matter that belongs in GQ and the medical queries that go in IMHO.)
Whenever I have a bad case of flu coming on, the skin of my lower back becomes tender. I don’t have a backache per se, just soreness in the dermis. It gives me advanced alert to start chugging vitamin C.
The top of my scalp becomes tender when I am ill with cough/cold/ flu symptoms. I suspect it’s an indication I have a virus. It’s a handy indicator as occasionally when I feel below par I can get early confirmation of an infection by patting the top of my head.
left side of my scalp gets tender to the touch. I had never previously associated it with cold of flu but is very possible since I had it last month for about two weeks and I also had the flu or something similar.
your body produces cytokines in order to try a “first line” defense against an invader, which causes the typical muscle pain, fatigue, etc. and are why so many viral infections are described as starting with “flu-like symptoms.”