I’ve noticed after a recent shoulder Op that I can have long periods relatively pain free, then without any additional aggravation or movement on the wound the pain comes back full force. What’s actually different? The gaps seem too long for the nerves just to have rested? Does the body repairing itself actually cause pain?
You’re right that it’s not just the nerves resting. That process does happen but it’s very fast (fractions of a second). Instead, this is caused by the brain itself getting fatigued by the constant input from the nerves and blocking them out. Then after a while it’s rested and ready to accept the input again.
You can see this same sort of thing happening if you stare at a pattern for a while. You’ll see the pattern fade out, with the light parts appearing darker and the dark parts appearing lighter, until it’s hard to see the pattern anymore. Then if you look at a blank space, the reverse of the pattern shows up. Your eyes and brain are blocking out the stimulation of the pattern, so when the pattern goes away the block actually creates a reverse pattern. However, if you instead keep staring at the pattern for a very long time, you’ll begin to see parts of the pattern fade in and out as your brain’s block fades and is replaced. This corresponds to the waves of pain you’re talking about.
Basically, your brain is able to get used to the pain, but it keeps checking occasionally to see if the pain is still there.
Pain is a way that your bodey uses to alert the mind of danger, so when there is an opening in the body and microspecs enter it causes more pain