Stop in for a cup of coffee

Morning!
Trying to rain here.
Rough night is an understatement.
Why would coffee cause the pain to taper off? Seems to every morning.
If I recall correctly, pain relievers such as Excedrin have caffeine in them. Evidently the caffeine increases the effectiveness of the pain relievers. I’m not going to pretend I know how or why, some kind of chemical voodoo.