Why would someone who pretty much never gets heartburn suddenly have it chronically for several days?

I don’t know what is going on. I have, over the past 3 or 4 days, had chronic, ongoing heartburn. The weird thing is that I rarely get heartburn, maybe once every year or two?

My diet hasn’t really changed, my activity hasn’t changed, I’m not especially stressed out.. yet I have been experiencing low-grade heartburn during the day (mostly ignorable) and then, of course, it flares up when I go to bed. I had to get up in the middle of the night last night to take some Tums, it was too bad to sleep.

Is this sudden change something I should be concerned about?