It’s the aging process unfortunately and the time in your life when you have to work out what foods make your acid reflux worse. It can be very depressing realising you can’t eat the foods you always have done in the past, my food shopping and cooking bears no resemblance to what I used to buy and cook when much younger.
Lying on your side is not good if you suffer with reflux, best propped up and laying on your back is best. Agreed stress makes it worse, but it's not easy to avoid that sometimes.