One of alcohol’s strongest selling points, per yer average Western movie dentist or surgeon, is as an analgesic.
I always think of the body as struggling towards equilibrium.
If you add another element to the balance, it adjusts the other way.
The body has a bunch of strategies for dealing with pain, mostly psychological.
However, if you pour in an analgesic pain reliever into your gullet every day for decades, your body probably discards a bunch of those strategies for dealing with pain, or they fall to disuse.
You stop drinking and everything just sort of hurts.
Even worse, habitual use of a painkiller allows you to damage yourself physically without noticing it so much.