Painkillers per say doesn't hide the gastric pain.
Prolonged usage of painkillers exacerbates the problems, it affects the barrier that is created to protect the stomach lining, hence predispose to the formation of gastric ulcers.

Unfortunately, I don't think so.
As we've learned in science and biology in school, our body has the ability to keep things in balance, which is called homeostasis.
For the stomach, it's natural environment is acidic (which helps in digestion of food / killing of bacteria/germs). Trying to "alkalize" it is pointless.

P.S. Same goes to oxygenated water which was the craze way back when, our stomach doesn't absorb oxygen. Just a scam in my opinion.

Additional point, don't think only acid can do damage to the body.

Alkaline burns are worse compared to acid burns on your skin / eye.

People always think ACID = corrossive. True but other stuffs can be worse.

Ohhh. Just a random name I put. Haha. Must be a coincidence.