Sounds painful! I'm 21" at the shoulder and almost always travel at the back although I try (and normally) get the window seat which at least allows be to spread over to one side a bit. I have noticed "hunched-shoulder syndrome" however, particular at meal times when trying not knock the neighbours meal flying when trying to carve up any meat!

One plus point, you realise that you have to get on with your neighbours (just like the real world!), particularly 15.5 hour long-haul flights.