As I responded in the aforementioned post, I too benefit from taking showers. I notice that period of relief during and afterwords.

I'm pretty sure the heat increases blood flow which in turn promotes healing. I agree that part of it has to do with endorphin release. I'm sure you feel better from this and after the two hours you are more or less back to baseline All in all this is one part of my life I'm thankful to still have and I usually take two showers a day.