I started to develop similar issues when I moved from the iPhone 5 to the 7 Plus. I sold that and got the 8 the next year, and I started using Popsockets and sw

I started to develop similar issues when I moved from the iPhone 5 to the 7 Plus. I sold that and got the 8 the next year, and I started using Popsockets and swapping hands and fingers more frequently, but I still have some numbness and pain in my right thumb joint. I really wish phones had stuck around the iPhone 4/5 screen size - even with fairly large hands, that felt just about perfect.