Sour taste

When I was on Lanzoprazole, food and drink started tasting unpleasant, so that might be the cause.

Thank you. I’m going to try stopping Lansoprazole and take Gaviscon for the heartburn. If it doesn’t help I will go to gp.

Yes, I took lansoprazole for a while, all ok, then had a break and when I went back on it, I didn't feel good and had a horrible taste (more like an onion) in my mouth for weeks which just wouldn't go.
My doctor referred me for a camera down my throat and was confirmed that I had barrets. He changed my medication to pantoprazole, and after a couple of weeks, all back to normal.
Maybe speak to your Gp and ask for a medication review.